global: snapshot

2026-05-30 07:29:27 -07:00 · 2026-01-12 22:43:56 +01:00
parent b675b70067
commit 5ffb66c0dc
39 changed files with 8207 additions and 11957 deletions
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1954,9 +1954,9 @@ dependencies = [

 [[package]]
 name = "importmap"
-version = "0.1.2"
+version = "0.1.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8d13d6361899f14d58146b6214c07e63cda8270c3ef3b8c30626f8e20e6766eb"
+checksum = "a45c4c5e8b4d0a6aed90f3a14125bd3af3bca73d49d44e8f8b764311903b5213"
 dependencies = [
 "rapidhash",
 "serde",
@@ -2684,7 +2684,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6db2770f06117d490610c7488547d543617b21bfa07796d7a12f6f1bd53850d1"
 dependencies = [
 "rand_chacha 0.9.0",
- "rand_core 0.9.3",
+ "rand_core 0.9.4",
 ]

 [[package]]
@@ -2704,7 +2704,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d3022b5f1df60f26e1ffddd6c66e8aa15de382ae63b3a0c1bfc0e4d3e3f325cb"
 dependencies = [
 "ppv-lite86",
- "rand_core 0.9.3",
+ "rand_core 0.9.4",
 ]

 [[package]]
@@ -2718,9 +2718,9 @@ dependencies = [

 [[package]]
 name = "rand_core"
-version = "0.9.3"
+version = "0.9.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "99d9a13982dcf210057a8a78572b2217b667c3beacbf3a0d8b454f6f82837d38"
+checksum = "4f1b3bc831f92381018fd9c6350b917c7b21f1eed35a65a51900e0e55a3d7afa"
 dependencies = [
 "getrandom 0.3.4",
 ]
@@ -2745,9 +2745,9 @@ dependencies = [

 [[package]]
 name = "rawdb"
-version = "0.5.8"
+version = "0.5.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a1eb09ba02f9467845fde4a1fadb317721025f2b836f22a5a7d3567c9e100875"
+checksum = "eb8999fc8f80521c13091f98e1a24bde2448b29c0637f008dc470ed84d58f703"
 dependencies = [
 "libc",
 "log",
@@ -3689,9 +3689,9 @@ checksum = "8f54a172d0620933a27a4360d3db3e2ae0dd6cceae9730751a036bbf182c4b23"

 [[package]]
 name = "vecdb"
-version = "0.5.8"
+version = "0.5.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0b7b02690e7c013257b959b482fac78e90f73764efa8a57551e1e67a06ad7ab4"
+checksum = "1a31985bee527adda1601eab9c72de0a567be83a08e80e646b79afb77ab14970"
 dependencies = [
 "ctrlc",
 "log",
@@ -3710,9 +3710,9 @@ dependencies = [

 [[package]]
 name = "vecdb_derive"
-version = "0.5.8"
+version = "0.5.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "21339c58345d1a422c2574b1114b3cd862900a9196421dc7acf43aca48c288bb"
+checksum = "61716cbeb322dcc9838cea11b533cea278f9592b2ef2ce520595849833cfee1c"
 dependencies = [
 "quote",
 "syn",
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -79,7 +79,7 @@ serde_json = { version = "1.0.149", features = ["float_roundtrip", "preserve_ord
 smallvec = "1.15.1"
 tokio = { version = "1.49.0", features = ["rt-multi-thread"] }
 tracing = { version = "0.1", default-features = false, features = ["std"] }
-vecdb = { version = "0.5.8", features = ["derive", "serde_json", "pco", "schemars"] }
+vecdb = { version = "0.5.9", features = ["derive", "serde_json", "pco", "schemars"] }
 # vecdb = { path = "../anydb/crates/vecdb", features = ["derive", "serde_json", "pco", "schemars"] }

 [workspace.metadata.release]
--- a/crates/brk_bindgen/src/analysis/names.rs
+++ b/crates/brk_bindgen/src/analysis/names.rs
@@ -458,4 +458,33 @@ mod tests {
            Some(&FieldNamePosition::Append("_cumulative".to_string()))
        );
    }
+
+    #[test]
+    fn test_analyze_pattern_level_no_base_field() {
+        // When there's no base field (like block_weight which has no block_weight metric),
+        // only suffixed metrics like block_weight_average, block_weight_sum, etc.
+        // Base should still be "block_weight"
+        let children = vec![
+            ("average".to_string(), "block_weight_average".to_string()),
+            ("sum".to_string(), "block_weight_sum".to_string()),
+            (
+                "cumulative".to_string(),
+                "block_weight_cumulative".to_string(),
+            ),
+            ("max".to_string(), "block_weight_max".to_string()),
+            ("min".to_string(), "block_weight_min".to_string()),
+        ];
+        let analysis = analyze_pattern_level(&children);
+
+        assert!(matches!(analysis.common, CommonDenominator::Prefix(_)));
+        assert_eq!(analysis.base, "block_weight");
+        assert_eq!(
+            analysis.field_positions.get("average"),
+            Some(&FieldNamePosition::Append("_average".to_string()))
+        );
+        assert_eq!(
+            analysis.field_positions.get("sum"),
+            Some(&FieldNamePosition::Append("_sum".to_string()))
+        );
+    }
 }
--- a/crates/brk_bindgen/src/analysis/tree.rs
+++ b/crates/brk_bindgen/src/analysis/tree.rs
@@ -7,7 +7,7 @@ use std::collections::{BTreeMap, BTreeSet, HashMap};

 use brk_types::{Index, TreeNode, extract_json_type};

-use crate::{IndexSetPattern, PatternField, analysis::names::analyze_pattern_level, child_type_name};
+use crate::{IndexSetPattern, PatternField, analysis::names::{analyze_pattern_level, CommonDenominator}, child_type_name};

 /// Get the first leaf name from a tree node.
 pub fn get_first_leaf_name(node: &TreeNode) -> Option<String> {
@@ -124,16 +124,81 @@ fn collect_indexes_from_tree(
    }
 }

+/// Result of analyzing a pattern instance's base.
+#[derive(Debug, Clone)]
+pub struct PatternBaseResult {
+    /// The computed base name for the pattern.
+    pub base: String,
+    /// Whether an outlier child was excluded to find the pattern.
+    /// If true, pattern factory should not be used.
+    pub has_outlier: bool,
+}
+
+impl PatternBaseResult {
+    /// Returns true if an inline type should be generated instead of using a pattern factory.
+    ///
+    /// This is the case when:
+    /// - The child fields don't match a parameterizable pattern, OR
+    /// - An outlier was detected during pattern analysis
+    pub fn should_inline(&self, is_parameterizable: bool) -> bool {
+        !is_parameterizable || self.has_outlier
+    }
+}
+
 /// Get the metric base for a pattern instance by analyzing direct children.
 ///
 /// Uses field names and first leaf names from direct children to determine
 /// the common base via `analyze_pattern_level`.
-pub fn get_pattern_instance_base(node: &TreeNode) -> String {
+///
+/// If the initial analysis fails to find a common pattern, it tries excluding
+/// each child one at a time to detect outliers (e.g., a mismatched "base" field
+/// from indexer/computed tree merging).
+///
+/// Returns both the base and whether an outlier was detected.
+pub fn get_pattern_instance_base(node: &TreeNode) -> PatternBaseResult {
    let child_names = get_direct_children_for_analysis(node);
    if child_names.is_empty() {
-        return String::new();
+        return PatternBaseResult {
+            base: String::new(),
+            has_outlier: false,
+        };
+    }
+
+    let analysis = analyze_pattern_level(&child_names);
+
+    // If we found a common pattern, use it
+    if !matches!(analysis.common, CommonDenominator::None) {
+        return PatternBaseResult {
+            base: analysis.base,
+            has_outlier: false,
+        };
+    }
+
+    // If no common pattern found, try excluding each child one at a time
+    // to detect if there's a single outlier breaking the pattern.
+    if child_names.len() > 2 {
+        for i in 0..child_names.len() {
+            let filtered: Vec<_> = child_names
+                .iter()
+                .enumerate()
+                .filter(|(j, _)| *j != i)
+                .map(|(_, v)| v.clone())
+                .collect();
+
+            let filtered_analysis = analyze_pattern_level(&filtered);
+            if !matches!(filtered_analysis.common, CommonDenominator::None) {
+                return PatternBaseResult {
+                    base: filtered_analysis.base,
+                    has_outlier: true,
+                };
+            }
+        }
+    }
+
+    PatternBaseResult {
+        base: analysis.base,
+        has_outlier: false,
    }
-    analyze_pattern_level(&child_names).base
 }

 /// Get (field_name, shortest_leaf_name) pairs for direct children of a branch node.
@@ -217,3 +282,93 @@ pub fn get_fields_with_child_info(
        })
        .collect()
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use brk_types::{MetricLeaf, MetricLeafWithSchema, TreeNode};
+    use std::collections::BTreeMap;
+
+    fn make_leaf(name: &str) -> TreeNode {
+        let leaf = MetricLeaf {
+            name: name.to_string(),
+            kind: "TestType".to_string(),
+            indexes: BTreeSet::new(),
+        };
+        TreeNode::Leaf(MetricLeafWithSchema::new(leaf, serde_json::json!({})))
+    }
+
+    fn make_branch(children: Vec<(&str, TreeNode)>) -> TreeNode {
+        let map: BTreeMap<String, TreeNode> = children
+            .into_iter()
+            .map(|(k, v)| (k.to_string(), v))
+            .collect();
+        TreeNode::Branch(map)
+    }
+
+    #[test]
+    fn test_get_pattern_instance_base_with_base_field() {
+        // Simulates vbytes tree: has base field with block_vbytes leaf
+        let tree = make_branch(vec![
+            ("base", make_branch(vec![("dateindex", make_leaf("block_vbytes"))])),
+            ("average", make_branch(vec![("dateindex", make_leaf("block_vbytes_average"))])),
+            ("sum", make_branch(vec![("dateindex", make_leaf("block_vbytes_sum"))])),
+        ]);
+
+        let result = get_pattern_instance_base(&tree);
+        assert_eq!(result.base, "block_vbytes");
+        assert!(!result.has_outlier);
+    }
+
+    #[test]
+    fn test_get_pattern_instance_base_without_base_field() {
+        // Simulates weight tree: NO base field, only suffixed metrics
+        let tree = make_branch(vec![
+            ("average", make_branch(vec![("dateindex", make_leaf("block_weight_average"))])),
+            ("sum", make_branch(vec![("dateindex", make_leaf("block_weight_sum"))])),
+            ("cumulative", make_branch(vec![("dateindex", make_leaf("block_weight_cumulative"))])),
+            ("max", make_branch(vec![("dateindex", make_leaf("block_weight_max"))])),
+            ("min", make_branch(vec![("dateindex", make_leaf("block_weight_min"))])),
+        ]);
+
+        let result = get_pattern_instance_base(&tree);
+        assert_eq!(result.base, "block_weight");
+        assert!(!result.has_outlier);
+    }
+
+    #[test]
+    fn test_get_pattern_instance_base_with_duplicate_base_field() {
+        // What if there's a "base" field that points to the same leaf as "average"?
+        // This could happen if the tree generation creates a base field that shares leaves with average
+        let tree = make_branch(vec![
+            ("base", make_branch(vec![("dateindex", make_leaf("block_weight_average"))])),
+            ("average", make_branch(vec![("dateindex", make_leaf("block_weight_average"))])),
+            ("sum", make_branch(vec![("dateindex", make_leaf("block_weight_sum"))])),
+        ]);
+
+        let result = get_pattern_instance_base(&tree);
+        // Common prefix among all children is "block_weight_"
+        assert_eq!(result.base, "block_weight");
+        assert!(!result.has_outlier);
+    }
+
+    #[test]
+    fn test_get_pattern_instance_base_with_mismatched_base_name() {
+        // Simulates the actual bug: indexed tree's "base" field has name "weight"
+        // but computed tree's derived metrics use "block_weight_*" prefix.
+        // After tree merge, we get a base field with mismatched naming.
+        let tree = make_branch(vec![
+            ("base", make_leaf("weight")), // Outlier - doesn't match pattern
+            ("average", make_leaf("block_weight_average")),
+            ("sum", make_leaf("block_weight_sum")),
+            ("cumulative", make_leaf("block_weight_cumulative")),
+            ("max", make_leaf("block_weight_max")),
+            ("min", make_leaf("block_weight_min")),
+        ]);
+
+        let result = get_pattern_instance_base(&tree);
+        // Should detect "weight" as outlier and find common prefix from others
+        assert_eq!(result.base, "block_weight");
+        assert!(result.has_outlier); // Pattern factory should NOT be used
+    }
+}
--- a/crates/brk_bindgen/src/generate/tree.rs
+++ b/crates/brk_bindgen/src/generate/tree.rs
@@ -4,16 +4,35 @@ use std::collections::{HashMap, HashSet};

 use brk_types::TreeNode;

-use crate::{ClientMetadata, PatternField, get_fields_with_child_info};
+use crate::{
+    ClientMetadata, PatternBaseResult, PatternField, child_type_name, get_fields_with_child_info,
+    get_pattern_instance_base,
+};
+
+/// Pre-computed context for a single child node.
+pub struct ChildContext<'a> {
+    /// The child's field name in the tree.
+    pub name: &'a str,
+    /// The child node.
+    pub node: &'a TreeNode,
+    /// The field info for this child.
+    pub field: PatternField,
+    /// Child fields if this is a branch (for pattern lookup).
+    pub child_fields: Option<Vec<PatternField>>,
+    /// Pattern analysis result.
+    pub base_result: PatternBaseResult,
+    /// Whether this is a leaf node.
+    pub is_leaf: bool,
+    /// Whether to use an inline type instead of a pattern factory (only meaningful for branches).
+    pub should_inline: bool,
+    /// The type name to use for inline branches.
+    pub inline_type_name: String,
+}

 /// Context for generating a tree node, returned by `prepare_tree_node`.
 pub struct TreeNodeContext<'a> {
-    /// The children of the branch node.
-    pub children: &'a std::collections::BTreeMap<String, TreeNode>,
-    /// Fields with optional child field info for generic pattern lookup.
-    pub fields_with_child_info: Vec<(PatternField, Option<Vec<PatternField>>)>,
-    /// Just the fields (for pattern lookup).
-    pub fields: Vec<PatternField>,
+    /// Pre-computed context for each child.
+    pub children: Vec<ChildContext<'a>>,
 }

 /// Prepare a tree node for generation.
@@ -26,20 +45,22 @@ pub fn prepare_tree_node<'a>(
    metadata: &ClientMetadata,
    generated: &mut HashSet<String>,
 ) -> Option<TreeNodeContext<'a>> {
-    let TreeNode::Branch(children) = node else {
+    let TreeNode::Branch(branch_children) = node else {
        return None;
    };

-    let fields_with_child_info = get_fields_with_child_info(children, name, pattern_lookup);
+    let fields_with_child_info = get_fields_with_child_info(branch_children, name, pattern_lookup);
    let fields: Vec<PatternField> = fields_with_child_info
        .iter()
        .map(|(f, _)| f.clone())
        .collect();

-    // Skip if this matches a parameterizable pattern
+    // Skip if this matches a parameterizable pattern AND has no outlier
+    let base_result = get_pattern_instance_base(node);
    if let Some(pattern_name) = pattern_lookup.get(&fields)
        && pattern_name != name
        && metadata.is_parameterizable(pattern_name)
+        && !base_result.has_outlier
    {
        return None;
    }
@@ -50,9 +71,38 @@ pub fn prepare_tree_node<'a>(
    }
    generated.insert(name.to_string());

-    Some(TreeNodeContext {
-        children,
-        fields_with_child_info,
-        fields,
-    })
+    // Build child contexts with pre-computed decisions
+    let children: Vec<ChildContext<'a>> = branch_children
+        .iter()
+        .zip(fields_with_child_info)
+        .map(|((child_name, child_node), (field, child_fields))| {
+            let is_leaf = matches!(child_node, TreeNode::Leaf(_));
+            let base_result = get_pattern_instance_base(child_node);
+            let is_parameterizable = child_fields
+                .as_ref()
+                .is_some_and(|cf| metadata.is_parameterizable_fields(cf));
+            // should_inline is only meaningful for branches
+            let should_inline = !is_leaf && base_result.should_inline(is_parameterizable);
+
+            // Inline type name (only used when should_inline is true)
+            let inline_type_name = if should_inline {
+                child_type_name(name, child_name)
+            } else {
+                String::new()
+            };
+
+            ChildContext {
+                name: child_name,
+                node: child_node,
+                field,
+                child_fields,
+                base_result,
+                is_leaf,
+                should_inline,
+                inline_type_name,
+            }
+        })
+        .collect();
+
+    Some(TreeNodeContext { children })
 }
--- a/crates/brk_bindgen/src/generators/javascript/client.rs
+++ b/crates/brk_bindgen/src/generators/javascript/client.rs
@@ -63,57 +63,65 @@ class BrkError extends Error {{
 * @property {{number}} end - End index (exclusive)
 * @property {{T[]}} data - The metric data
 */
-/** @typedef {{MetricData<unknown>}} AnyMetricData */
+/** @typedef {{MetricData<any>}} AnyMetricData */

 /**
+ * Thenable interface for await support.
+ * @template T
+ * @typedef {{(onfulfilled?: (value: MetricData<T>) => MetricData<T>, onrejected?: (reason: Error) => never) => Promise<MetricData<T>>}} Thenable
+ */
+
+/**
+ * Metric endpoint builder. Callable (returns itself) so both .by.dateindex and .by.dateindex() work.
 * @template T
 * @typedef {{Object}} MetricEndpointBuilder
- * @property {{(n: number) => RangeBuilder<T>}} first - Fetch first n data points
- * @property {{(n: number) => RangeBuilder<T>}} last - Fetch last n data points
- * @property {{(start: number, end: number) => RangeBuilder<T>}} range - Set explicit range [start, end)
- * @property {{(start: number) => FromBuilder<T>}} from - Set start position, chain with take() or to()
- * @property {{(end: number) => ToBuilder<T>}} to - Set end position, chain with takeLast() or from()
- * @property {{(onUpdate?: (value: MetricData<T>) => void) => Promise<MetricData<T>>}} json - Execute and return JSON (all data)
- * @property {{() => Promise<string>}} csv - Execute and return CSV (all data)
+ * @property {{(index: number) => SingleItemBuilder<T>}} get - Get single item at index
+ * @property {{(start?: number, end?: number) => RangeBuilder<T>}} slice - Slice like Array.slice
+ * @property {{(n: number) => RangeBuilder<T>}} first - Get first n items
+ * @property {{(n: number) => RangeBuilder<T>}} last - Get last n items
+ * @property {{(n: number) => SkippedBuilder<T>}} skip - Skip first n items, chain with take()
+ * @property {{(onUpdate?: (value: MetricData<T>) => void) => Promise<MetricData<T>>}} fetch - Fetch all data
+ * @property {{() => Promise<string>}} fetchCsv - Fetch all data as CSV
+ * @property {{Thenable<T>}} then - Thenable (await endpoint)
 * @property {{string}} path - The endpoint path
 */
-/** @typedef {{MetricEndpointBuilder<unknown>}} AnyMetricEndpointBuilder */
+/** @typedef {{MetricEndpointBuilder<any>}} AnyMetricEndpointBuilder */

 /**
 * @template T
- * @typedef {{Object}} FromBuilder
- * @property {{(n: number) => RangeBuilder<T>}} take - Take n items from start position
- * @property {{(end: number) => RangeBuilder<T>}} to - Set end position
- * @property {{(onUpdate?: (value: MetricData<T>) => void) => Promise<MetricData<T>>}} json - Execute and return JSON
- * @property {{() => Promise<string>}} csv - Execute and return CSV
+ * @typedef {{Object}} SingleItemBuilder
+ * @property {{(onUpdate?: (value: MetricData<T>) => void) => Promise<MetricData<T>>}} fetch - Fetch the item
+ * @property {{() => Promise<string>}} fetchCsv - Fetch as CSV
+ * @property {{Thenable<T>}} then - Thenable
 */

 /**
 * @template T
- * @typedef {{Object}} ToBuilder
- * @property {{(n: number) => RangeBuilder<T>}} takeLast - Take last n items before end position
- * @property {{(start: number) => RangeBuilder<T>}} from - Set start position
- * @property {{(onUpdate?: (value: MetricData<T>) => void) => Promise<MetricData<T>>}} json - Execute and return JSON
- * @property {{() => Promise<string>}} csv - Execute and return CSV
+ * @typedef {{Object}} SkippedBuilder
+ * @property {{(n: number) => RangeBuilder<T>}} take - Take n items after skipped position
+ * @property {{(onUpdate?: (value: MetricData<T>) => void) => Promise<MetricData<T>>}} fetch - Fetch from skipped position to end
+ * @property {{() => Promise<string>}} fetchCsv - Fetch as CSV
+ * @property {{Thenable<T>}} then - Thenable
 */

 /**
 * @template T
 * @typedef {{Object}} RangeBuilder
- * @property {{(onUpdate?: (value: MetricData<T>) => void) => Promise<MetricData<T>>}} json - Execute and return JSON
- * @property {{() => Promise<string>}} csv - Execute and return CSV
+ * @property {{(onUpdate?: (value: MetricData<T>) => void) => Promise<MetricData<T>>}} fetch - Fetch the range
+ * @property {{() => Promise<string>}} fetchCsv - Fetch as CSV
+ * @property {{Thenable<T>}} then - Thenable
 */

 /**
 * @template T
 * @typedef {{Object}} MetricPattern
 * @property {{string}} name - The metric name
- * @property {{Partial<Record<Index, MetricEndpointBuilder<T>>>}} by - Index endpoints (lazy getters)
+ * @property {{Readonly<Partial<Record<Index, MetricEndpointBuilder<T>>>>}} by - Index endpoints as lazy getters. Access via .by.dateindex or .by['dateindex']
 * @property {{() => Index[]}} indexes - Get the list of available indexes
 * @property {{(index: Index) => MetricEndpointBuilder<T>|undefined}} get - Get an endpoint for a specific index
 */

-/** @typedef {{MetricPattern<unknown>}} AnyMetricPattern */
+/** @typedef {{MetricPattern<any>}} AnyMetricPattern */

 /**
 * Create a metric endpoint builder with typestate pattern.
@@ -147,50 +155,46 @@ function _endpoint(client, name, index) {{
   * @returns {{RangeBuilder<T>}}
   */
  const rangeBuilder = (start, end) => ({{
-    json(/** @type {{((value: MetricData<T>) => void) | undefined}} */ onUpdate) {{
-      return client.getJson(buildPath(start, end), onUpdate);
-    }},
-    csv() {{ return client.getText(buildPath(start, end, 'csv')); }},
+    fetch(onUpdate) {{ return client.getJson(buildPath(start, end), onUpdate); }},
+    fetchCsv() {{ return client.getText(buildPath(start, end, 'csv')); }},
+    then(resolve, reject) {{ return this.fetch().then(resolve, reject); }},
+  }});
+
+  /**
+   * @param {{number}} index
+   * @returns {{SingleItemBuilder<T>}}
+   */
+  const singleItemBuilder = (index) => ({{
+    fetch(onUpdate) {{ return client.getJson(buildPath(index, index + 1), onUpdate); }},
+    fetchCsv() {{ return client.getText(buildPath(index, index + 1, 'csv')); }},
+    then(resolve, reject) {{ return this.fetch().then(resolve, reject); }},
  }});

  /**
   * @param {{number}} start
-   * @returns {{FromBuilder<T>}}
+   * @returns {{SkippedBuilder<T>}}
   */
-  const fromBuilder = (start) => ({{
-    take(/** @type {{number}} */ n) {{ return rangeBuilder(start, start + n); }},
-    to(/** @type {{number}} */ end) {{ return rangeBuilder(start, end); }},
-    json(/** @type {{((value: MetricData<T>) => void) | undefined}} */ onUpdate) {{
-      return client.getJson(buildPath(start, undefined), onUpdate);
-    }},
-    csv() {{ return client.getText(buildPath(start, undefined, 'csv')); }},
+  const skippedBuilder = (start) => ({{
+    take(n) {{ return rangeBuilder(start, start + n); }},
+    fetch(onUpdate) {{ return client.getJson(buildPath(start, undefined), onUpdate); }},
+    fetchCsv() {{ return client.getText(buildPath(start, undefined, 'csv')); }},
+    then(resolve, reject) {{ return this.fetch().then(resolve, reject); }},
  }});

-  /**
-   * @param {{number}} end
-   * @returns {{ToBuilder<T>}}
-   */
-  const toBuilder = (end) => ({{
-    takeLast(/** @type {{number}} */ n) {{ return rangeBuilder(end - n, end); }},
-    from(/** @type {{number}} */ start) {{ return rangeBuilder(start, end); }},
-    json(/** @type {{((value: MetricData<T>) => void) | undefined}} */ onUpdate) {{
-      return client.getJson(buildPath(undefined, end), onUpdate);
-    }},
-    csv() {{ return client.getText(buildPath(undefined, end, 'csv')); }},
-  }});
-
-  return {{
-    first(/** @type {{number}} */ n) {{ return rangeBuilder(undefined, n); }},
-    last(/** @type {{number}} */ n) {{ return rangeBuilder(-n, undefined); }},
-    range(/** @type {{number}} */ start, /** @type {{number}} */ end) {{ return rangeBuilder(start, end); }},
-    from(/** @type {{number}} */ start) {{ return fromBuilder(start); }},
-    to(/** @type {{number}} */ end) {{ return toBuilder(end); }},
-    json(/** @type {{((value: MetricData<T>) => void) | undefined}} */ onUpdate) {{
-      return client.getJson(buildPath(), onUpdate);
-    }},
-    csv() {{ return client.getText(buildPath(undefined, undefined, 'csv')); }},
+  /** @type {{MetricEndpointBuilder<T>}} */
+  const endpoint = {{
+    get(index) {{ return singleItemBuilder(index); }},
+    slice(start, end) {{ return rangeBuilder(start, end); }},
+    first(n) {{ return rangeBuilder(undefined, n); }},
+    last(n) {{ return rangeBuilder(-n, undefined); }},
+    skip(n) {{ return skippedBuilder(n); }},
+    fetch(onUpdate) {{ return client.getJson(buildPath(), onUpdate); }},
+    fetchCsv() {{ return client.getText(buildPath(undefined, undefined, 'csv')); }},
+    then(resolve, reject) {{ return this.fetch().then(resolve, reject); }},
    get path() {{ return p; }},
  }};
+
+  return endpoint;
 }}

 /**
@@ -235,7 +239,7 @@ class BrkClientBase {{
    const cachedJson = cachedRes ? await cachedRes.json() : null;

    if (cachedJson) onUpdate?.(cachedJson);
-    if (!globalThis.navigator?.onLine) {{
+    if (globalThis.navigator?.onLine === false) {{
      if (cachedJson) return cachedJson;
      throw new BrkError('Offline and no cached data available');
    }}
@@ -305,7 +309,11 @@ pub fn generate_static_constants(output: &mut String) {
    fn instance_const_camel<T: Serialize>(output: &mut String, name: &str, value: &T) {
        let json_value: Value = serde_json::to_value(value).unwrap();
        let camel_value = camel_case_top_level_keys(json_value);
-        write_static_const(output, name, &serde_json::to_string_pretty(&camel_value).unwrap());
+        write_static_const(
+            output,
+            name,
+            &serde_json::to_string_pretty(&camel_value).unwrap(),
+        );
    }

    instance_const_camel(output, "TERM_NAMES", &TERM_NAMES);
@@ -336,13 +344,25 @@ fn camel_case_top_level_keys(value: Value) -> Value {
 fn indent_json_const(json: &str) -> String {
    json.lines()
        .enumerate()
-        .map(|(i, line)| if i == 0 { line.to_string() } else { format!("  {}", line) })
+        .map(|(i, line)| {
+            if i == 0 {
+                line.to_string()
+            } else {
+                format!("  {}", line)
+            }
+        })
        .collect::<Vec<_>>()
        .join("\n")
 }

 fn write_static_const(output: &mut String, name: &str, json: &str) {
-    writeln!(output, "  {} = /** @type {{const}} */ ({});\n", name, indent_json_const(json)).unwrap();
+    writeln!(
+        output,
+        "  {} = /** @type {{const}} */ ({});\n",
+        name,
+        indent_json_const(json)
+    )
+    .unwrap();
 }

 /// Generate index accessor factory functions.
@@ -354,14 +374,30 @@ pub fn generate_index_accessors(output: &mut String, patterns: &[IndexSetPattern
    writeln!(output, "// Index accessor factory functions\n").unwrap();

    for pattern in patterns {
+        // Use 'readonly' to indicate these are getters (lazy evaluation)
        let by_fields: Vec<String> = pattern
            .indexes
            .iter()
-            .map(|idx| format!("{}: MetricEndpointBuilder<T>", idx.serialize_long()))
+            .map(|idx| {
+                format!(
+                    "readonly {}: MetricEndpointBuilder<T>",
+                    idx.serialize_long()
+                )
+            })
            .collect();
        let by_type = format!("{{ {} }}", by_fields.join(", "));

        writeln!(output, "/**").unwrap();
+        writeln!(
+            output,
+            " * Metric pattern with index endpoints as lazy getters."
+        )
+        .unwrap();
+        writeln!(
+            output,
+            " * Access via property (.by.dateindex) or bracket notation (.by['dateindex'])."
+        )
+        .unwrap();
        writeln!(output, " * @template T").unwrap();
        writeln!(
            output,
@@ -385,7 +421,11 @@ pub fn generate_index_accessors(output: &mut String, patterns: &[IndexSetPattern

        for (i, index) in pattern.indexes.iter().enumerate() {
            let index_name = index.serialize_long();
-            let comma = if i < pattern.indexes.len() - 1 { "," } else { "" };
+            let comma = if i < pattern.indexes.len() - 1 {
+                ","
+            } else {
+                ""
+            };
            writeln!(
                output,
                "      get {}() {{ return _endpoint(client, name, '{}'); }}{}",
@@ -438,8 +478,12 @@ pub fn generate_structural_patterns(
        }
        writeln!(output, " * @typedef {{Object}} {}", pattern.name).unwrap();
        for field in &pattern.fields {
-            let js_type =
-                metadata.field_type_annotation(field, pattern.is_generic, None, GenericSyntax::JAVASCRIPT);
+            let js_type = metadata.field_type_annotation(
+                field,
+                pattern.is_generic,
+                None,
+                GenericSyntax::JAVASCRIPT,
+            );
            writeln!(
                output,
                " * @property {{{}}} {}",
@@ -469,8 +513,17 @@ pub fn generate_structural_patterns(
        writeln!(output, " * @returns {{{}}}", return_type).unwrap();
        writeln!(output, " */").unwrap();

-        let param_name = if is_parameterizable { "acc" } else { "basePath" };
-        writeln!(output, "function create{}(client, {}) {{", pattern.name, param_name).unwrap();
+        let param_name = if is_parameterizable {
+            "acc"
+        } else {
+            "basePath"
+        };
+        writeln!(
+            output,
+            "function create{}(client, {}) {{",
+            pattern.name, param_name
+        )
+        .unwrap();
        writeln!(output, "  return {{").unwrap();

        let syntax = JavaScriptSyntax;
--- a/crates/brk_bindgen/src/generators/javascript/tree.rs
+++ b/crates/brk_bindgen/src/generators/javascript/tree.rs
@@ -6,7 +6,7 @@ use std::fmt::Write;
 use brk_types::TreeNode;

 use crate::{
-    ClientMetadata, Endpoint, GenericSyntax, JavaScriptSyntax, PatternField, child_type_name,
+    ClientMetadata, Endpoint, GenericSyntax, JavaScriptSyntax, PatternField,
    generate_leaf_field, get_first_leaf_name, get_node_fields, get_pattern_instance_base,
    infer_accumulated_name, prepare_tree_node, to_camel_case,
 };
@@ -45,43 +45,41 @@ fn generate_tree_typedef(
    writeln!(output, "/**").unwrap();
    writeln!(output, " * @typedef {{Object}} {}", name).unwrap();

-    for ((field, child_fields), (child_name, _)) in
-        ctx.fields_with_child_info.iter().zip(ctx.children.iter())
-    {
-        let js_type = metadata.resolve_tree_field_type(
-            field,
-            child_fields.as_deref(),
-            name,
-            child_name,
-            GenericSyntax::JAVASCRIPT,
-        );
+    for child in &ctx.children {
+        let js_type = if child.should_inline {
+            child.inline_type_name.clone()
+        } else {
+            metadata.resolve_tree_field_type(
+                &child.field,
+                child.child_fields.as_deref(),
+                name,
+                child.name,
+                GenericSyntax::JAVASCRIPT,
+            )
+        };

        writeln!(
            output,
            " * @property {{{}}} {}",
            js_type,
-            to_camel_case(&field.name)
+            to_camel_case(&child.field.name)
        )
        .unwrap();
    }

    writeln!(output, " */\n").unwrap();

-    for (child_name, child_node) in ctx.children {
-        if let TreeNode::Branch(grandchildren) = child_node {
-            let child_fields = get_node_fields(grandchildren, pattern_lookup);
-            // Generate typedef if no pattern match OR pattern is not parameterizable
-            if !metadata.is_parameterizable_fields(&child_fields) {
-                let child_type = child_type_name(name, child_name);
-                generate_tree_typedef(
-                    output,
-                    &child_type,
-                    child_node,
-                    pattern_lookup,
-                    metadata,
-                    generated,
-                );
-            }
+    // Generate child typedefs
+    for child in &ctx.children {
+        if child.should_inline {
+            generate_tree_typedef(
+                output,
+                &child.inline_type_name,
+                child.node,
+                pattern_lookup,
+                metadata,
+                generated,
+            );
        }
    }
 }
@@ -182,12 +180,14 @@ fn generate_tree_initializer(
                        .get(&child_fields)
                        .filter(|name| metadata.is_parameterizable(name));

-                    if let Some(pattern_name) = pattern_name {
-                        let arg = get_pattern_instance_base(child_node);
+                    let base_result = get_pattern_instance_base(child_node);
+
+                    // Use pattern factory only if no outlier was detected
+                    if let Some(pattern_name) = pattern_name.filter(|_| !base_result.has_outlier) {
                        writeln!(
                            output,
                            "{}{}: create{}(this, '{}'),",
-                            indent_str, field_name, pattern_name, arg
+                            indent_str, field_name, pattern_name, base_result.base
                        )
                        .unwrap();
                    } else {
--- a/crates/brk_bindgen/src/generators/python/client.rs
+++ b/crates/brk_bindgen/src/generators/python/client.rs
@@ -195,143 +195,138 @@ class _EndpointConfig:


 class RangeBuilder(Generic[T]):
-    """Final builder with range fully specified. Can only call json() or csv()."""
+    """Builder with range specified."""

    def __init__(self, config: _EndpointConfig):
        self._config = config

-    def json(self) -> MetricData[T]:
-        """Execute the query and return parsed JSON data."""
+    def fetch(self) -> MetricData[T]:
+        """Fetch the range as parsed JSON."""
        return self._config.get_json()

-    def csv(self) -> str:
-        """Execute the query and return CSV data as a string."""
+    def fetch_csv(self) -> str:
+        """Fetch the range as CSV string."""
        return self._config.get_csv()


-class FromBuilder(Generic[T]):
-    """Builder after calling from(start). Can chain with take() or to()."""
+class SingleItemBuilder(Generic[T]):
+    """Builder for single item access."""
+
+    def __init__(self, config: _EndpointConfig):
+        self._config = config
+
+    def fetch(self) -> MetricData[T]:
+        """Fetch the single item."""
+        return self._config.get_json()
+
+    def fetch_csv(self) -> str:
+        """Fetch as CSV."""
+        return self._config.get_csv()
+
+
+class SkippedBuilder(Generic[T]):
+    """Builder after calling skip(n). Chain with take() to specify count."""

    def __init__(self, config: _EndpointConfig):
        self._config = config

    def take(self, n: int) -> RangeBuilder[T]:
-        """Take n items from the start position."""
+        """Take n items after the skipped position."""
        start = self._config.start or 0
        return RangeBuilder(_EndpointConfig(
            self._config.client, self._config.name, self._config.index,
            start, start + n
        ))

-    def to(self, end: int) -> RangeBuilder[T]:
-        """Set the end position."""
-        return RangeBuilder(_EndpointConfig(
-            self._config.client, self._config.name, self._config.index,
-            self._config.start, end
-        ))
-
-    def json(self) -> MetricData[T]:
-        """Execute the query and return parsed JSON data (from start to end of data)."""
+    def fetch(self) -> MetricData[T]:
+        """Fetch from skipped position to end."""
        return self._config.get_json()

-    def csv(self) -> str:
-        """Execute the query and return CSV data as a string."""
-        return self._config.get_csv()
-
-
-class ToBuilder(Generic[T]):
-    """Builder after calling to(end). Can chain with take_last() or from()."""
-
-    def __init__(self, config: _EndpointConfig):
-        self._config = config
-
-    def take_last(self, n: int) -> RangeBuilder[T]:
-        """Take last n items before the end position."""
-        end = self._config.end or 0
-        return RangeBuilder(_EndpointConfig(
-            self._config.client, self._config.name, self._config.index,
-            end - n, end
-        ))
-
-    def from_(self, start: int) -> RangeBuilder[T]:
-        """Set the start position."""
-        return RangeBuilder(_EndpointConfig(
-            self._config.client, self._config.name, self._config.index,
-            start, self._config.end
-        ))
-
-    def json(self) -> MetricData[T]:
-        """Execute the query and return parsed JSON data (from start of data to end)."""
-        return self._config.get_json()
-
-    def csv(self) -> str:
-        """Execute the query and return CSV data as a string."""
+    def fetch_csv(self) -> str:
+        """Fetch as CSV."""
        return self._config.get_csv()


 class MetricEndpointBuilder(Generic[T]):
-    """Initial builder for metric endpoint queries.
+    """Builder for metric endpoint queries.

-    Use method chaining to specify the data range, then call json() or csv() to execute.
+    Use method chaining to specify the data range, then call fetch() or fetch_csv() to execute.

    Examples:
-        # Get all data
-        endpoint.json()
+        # Fetch all data
+        data = endpoint.fetch()

-        # Get last 10 points
-        endpoint.last(10).json()
+        # Single item access
+        data = endpoint[5].fetch()

-        # Get range [100, 200)
-        endpoint.range(100, 200).json()
+        # Slice syntax (Python-native)
+        data = endpoint[:10].fetch()      # First 10
+        data = endpoint[-5:].fetch()      # Last 5
+        data = endpoint[100:110].fetch()  # Range

-        # Get 10 points starting from position 100
-        endpoint.from_(100).take(10).json()
+        # Convenience methods (pandas-style)
+        data = endpoint.head().fetch()    # First 10 (default)
+        data = endpoint.head(20).fetch()  # First 20
+        data = endpoint.tail(5).fetch()   # Last 5
+
+        # Iterator-style chaining
+        data = endpoint.skip(100).take(10).fetch()
    """

    def __init__(self, client: BrkClientBase, name: str, index: Index):
        self._config = _EndpointConfig(client, name, index)

-    def first(self, n: int) -> RangeBuilder[T]:
-        """Fetch the first n data points."""
+    @overload
+    def __getitem__(self, key: int) -> SingleItemBuilder[T]: ...
+    @overload
+    def __getitem__(self, key: slice) -> RangeBuilder[T]: ...
+
+    def __getitem__(self, key: Union[int, slice]) -> Union[SingleItemBuilder[T], RangeBuilder[T]]:
+        """Access single item or slice.
+
+        Examples:
+            endpoint[5]        # Single item at index 5
+            endpoint[:10]      # First 10
+            endpoint[-5:]      # Last 5
+            endpoint[100:110]  # Range 100-109
+        """
+        if isinstance(key, int):
+            return SingleItemBuilder(_EndpointConfig(
+                self._config.client, self._config.name, self._config.index,
+                key, key + 1
+            ))
+        return RangeBuilder(_EndpointConfig(
+            self._config.client, self._config.name, self._config.index,
+            key.start, key.stop
+        ))
+
+    def head(self, n: int = 10) -> RangeBuilder[T]:
+        """Get the first n items (pandas-style)."""
        return RangeBuilder(_EndpointConfig(
            self._config.client, self._config.name, self._config.index,
            None, n
        ))

-    def last(self, n: int) -> RangeBuilder[T]:
-        """Fetch the last n data points."""
+    def tail(self, n: int = 10) -> RangeBuilder[T]:
+        """Get the last n items (pandas-style)."""
        return RangeBuilder(_EndpointConfig(
            self._config.client, self._config.name, self._config.index,
            -n, None
        ))

-    def range(self, start: int, end: int) -> RangeBuilder[T]:
-        """Set an explicit range [start, end)."""
-        return RangeBuilder(_EndpointConfig(
+    def skip(self, n: int) -> SkippedBuilder[T]:
+        """Skip the first n items. Chain with take() to get a range."""
+        return SkippedBuilder(_EndpointConfig(
            self._config.client, self._config.name, self._config.index,
-            start, end
+            n, None
        ))

-    def from_(self, start: int) -> FromBuilder[T]:
-        """Set the start position. Chain with take() or to()."""
-        return FromBuilder(_EndpointConfig(
-            self._config.client, self._config.name, self._config.index,
-            start, None
-        ))
-
-    def to(self, end: int) -> ToBuilder[T]:
-        """Set the end position. Chain with take_last() or from_()."""
-        return ToBuilder(_EndpointConfig(
-            self._config.client, self._config.name, self._config.index,
-            None, end
-        ))
-
-    def json(self) -> MetricData[T]:
-        """Execute the query and return parsed JSON data (all data)."""
+    def fetch(self) -> MetricData[T]:
+        """Fetch all data as parsed JSON."""
        return self._config.get_json()

-    def csv(self) -> str:
-        """Execute the query and return CSV data as a string (all data)."""
+    def fetch_csv(self) -> str:
+        """Fetch all data as CSV string."""
        return self._config.get_csv()

    def path(self) -> str:
--- a/crates/brk_bindgen/src/generators/python/mod.rs
+++ b/crates/brk_bindgen/src/generators/python/mod.rs
@@ -26,7 +26,7 @@ pub fn generate_python_client(
    writeln!(output, "# Do not edit manually\n").unwrap();
    writeln!(
        output,
-        "from typing import TypeVar, Generic, Any, Optional, List, Literal, TypedDict, Union, Protocol"
+        "from typing import TypeVar, Generic, Any, Optional, List, Literal, TypedDict, Union, Protocol, overload"
    )
    .unwrap();
    writeln!(output, "from http.client import HTTPSConnection, HTTPConnection").unwrap();
--- a/crates/brk_bindgen/src/generators/python/tree.rs
+++ b/crates/brk_bindgen/src/generators/python/tree.rs
@@ -6,8 +6,8 @@ use std::fmt::Write;
 use brk_types::TreeNode;

 use crate::{
-    ClientMetadata, GenericSyntax, PatternField, PythonSyntax, child_type_name, generate_leaf_field,
-    get_node_fields, get_pattern_instance_base, prepare_tree_node, to_snake_case,
+    ClientMetadata, GenericSyntax, PatternField, PythonSyntax, generate_leaf_field,
+    prepare_tree_node, to_snake_case,
 };

 /// Generate tree classes
@@ -41,22 +41,16 @@ fn generate_tree_class(

    // Generate child classes FIRST (post-order traversal)
    // This ensures children are defined before parent references them
-    for (child_name, child_node) in ctx.children.iter() {
-        if let TreeNode::Branch(grandchildren) = child_node {
-            let child_fields = get_node_fields(grandchildren, pattern_lookup);
-
-            // Generate inline class if no pattern match OR pattern is not parameterizable
-            if !metadata.is_parameterizable_fields(&child_fields) {
-                let child_class = child_type_name(name, child_name);
-                generate_tree_class(
-                    output,
-                    &child_class,
-                    child_node,
-                    pattern_lookup,
-                    metadata,
-                    generated,
-                );
-            }
+    for child in &ctx.children {
+        if child.should_inline {
+            generate_tree_class(
+                output,
+                &child.inline_type_name,
+                child.node,
+                pattern_lookup,
+                metadata,
+                generated,
+            );
        }
    }

@@ -71,45 +65,36 @@ fn generate_tree_class(
    .unwrap();

    let syntax = PythonSyntax;
-    for ((field, child_fields_opt), (child_name, child_node)) in
-        ctx.fields_with_child_info.iter().zip(ctx.children.iter())
-    {
-        let py_type = metadata.resolve_tree_field_type(
-            field,
-            child_fields_opt.as_deref(),
-            name,
-            child_name,
-            GenericSyntax::PYTHON,
-        );
-        let field_name_py = to_snake_case(&field.name);
+    for child in &ctx.children {
+        let field_name_py = to_snake_case(child.name);

-        if metadata.is_pattern_type(&field.rust_type) && metadata.is_parameterizable(&field.rust_type)
-        {
-            // Parameterizable pattern: use pattern class with metric base
-            let metric_base = get_pattern_instance_base(child_node);
-            writeln!(
-                output,
-                "        self.{}: {} = {}(client, '{}')",
-                field_name_py, py_type, field.rust_type, metric_base
-            )
-            .unwrap();
-        } else if let TreeNode::Leaf(leaf) = child_node {
-            // Leaf node: use shared helper
-            generate_leaf_field(output, &syntax, "client", child_name, leaf, metadata, "        ");
-        } else if field.is_branch() {
-            // Non-parameterizable pattern or regular branch: generate inline class
-            let inline_class = child_type_name(name, &field.name);
+        if child.is_leaf {
+            if let TreeNode::Leaf(leaf) = child.node {
+                generate_leaf_field(output, &syntax, "client", child.name, leaf, metadata, "        ");
+            }
+        } else if child.should_inline {
+            // Inline class
            writeln!(
                output,
                "        self.{}: {} = {}(client)",
-                field_name_py, inline_class, inline_class
+                field_name_py, child.inline_type_name, child.inline_type_name
            )
            .unwrap();
        } else {
-            panic!(
-                "Field '{}' has no matching index pattern. All metrics must be indexed.",
-                field.name
+            // Use pattern class with metric base
+            let py_type = metadata.resolve_tree_field_type(
+                &child.field,
+                child.child_fields.as_deref(),
+                name,
+                child.name,
+                GenericSyntax::PYTHON,
            );
+            writeln!(
+                output,
+                "        self.{}: {} = {}(client, '{}')",
+                field_name_py, py_type, child.field.rust_type, child.base_result.base
+            )
+            .unwrap();
        }
    }

--- a/crates/brk_bindgen/src/generators/rust/client.rs
+++ b/crates/brk_bindgen/src/generators/rust/client.rs
@@ -12,6 +12,7 @@ pub fn generate_imports(output: &mut String) {
    writeln!(
        output,
        r#"use std::sync::Arc;
+use std::ops::{{Bound, RangeBounds}};
 use serde::de::DeserializeOwned;
 pub use brk_cohort::*;
 pub use brk_types::*;
@@ -193,21 +194,30 @@ impl EndpointConfig {{

 /// Initial builder for metric endpoint queries.
 ///
-/// Use method chaining to specify the data range, then call `json()` or `csv()` to execute.
+/// Use method chaining to specify the data range, then call `fetch()` or `fetch_csv()` to execute.
 ///
 /// # Examples
 /// ```ignore
-/// // Get all data
-/// endpoint.json()?;
+/// // Fetch all data
+/// let data = endpoint.fetch()?;
 ///
-/// // Get last 10 points
-/// endpoint.last(10).json()?;
+/// // Get single item at index 5
+/// let data = endpoint.get(5).fetch()?;
+///
+/// // Get first 10 using range
+/// let data = endpoint.range(..10).fetch()?;
 ///
 /// // Get range [100, 200)
-/// endpoint.range(100, 200).json()?;
+/// let data = endpoint.range(100..200).fetch()?;
 ///
-/// // Get 10 points starting from position 100
-/// endpoint.from(100).take(10).json()?;
+/// // Get first 10 (convenience)
+/// let data = endpoint.take(10).fetch()?;
+///
+/// // Get last 10
+/// let data = endpoint.last(10).fetch()?;
+///
+/// // Iterator-style chaining
+/// let data = endpoint.skip(100).take(10).fetch()?;
 /// ```
 pub struct MetricEndpointBuilder<T> {{
    config: EndpointConfig,
@@ -219,44 +229,59 @@ impl<T: DeserializeOwned> MetricEndpointBuilder<T> {{
        Self {{ config: EndpointConfig::new(client, name, index), _marker: std::marker::PhantomData }}
    }}

-    /// Fetch the first n data points.
-    pub fn first(mut self, n: u64) -> RangeBuilder<T> {{
-        self.config.end = Some(n as i64);
+    /// Select a specific index position.
+    pub fn get(mut self, index: usize) -> SingleItemBuilder<T> {{
+        self.config.start = Some(index as i64);
+        self.config.end = Some(index as i64 + 1);
+        SingleItemBuilder {{ config: self.config, _marker: std::marker::PhantomData }}
+    }}
+
+    /// Select a range using Rust range syntax.
+    ///
+    /// # Examples
+    /// ```ignore
+    /// endpoint.range(..10)      // first 10
+    /// endpoint.range(100..110)  // indices 100-109
+    /// endpoint.range(100..)     // from 100 to end
+    /// ```
+    pub fn range<R: RangeBounds<usize>>(mut self, range: R) -> RangeBuilder<T> {{
+        self.config.start = match range.start_bound() {{
+            Bound::Included(&n) => Some(n as i64),
+            Bound::Excluded(&n) => Some(n as i64 + 1),
+            Bound::Unbounded => None,
+        }};
+        self.config.end = match range.end_bound() {{
+            Bound::Included(&n) => Some(n as i64 + 1),
+            Bound::Excluded(&n) => Some(n as i64),
+            Bound::Unbounded => None,
+        }};
        RangeBuilder {{ config: self.config, _marker: std::marker::PhantomData }}
    }}

-    /// Fetch the last n data points.
-    pub fn last(mut self, n: u64) -> RangeBuilder<T> {{
+    /// Take the first n items.
+    pub fn take(self, n: usize) -> RangeBuilder<T> {{
+        self.range(..n)
+    }}
+
+    /// Take the last n items.
+    pub fn last(mut self, n: usize) -> RangeBuilder<T> {{
        self.config.start = Some(-(n as i64));
        RangeBuilder {{ config: self.config, _marker: std::marker::PhantomData }}
    }}

-    /// Set an explicit range [start, end).
-    pub fn range(mut self, start: i64, end: i64) -> RangeBuilder<T> {{
-        self.config.start = Some(start);
-        self.config.end = Some(end);
-        RangeBuilder {{ config: self.config, _marker: std::marker::PhantomData }}
+    /// Skip the first n items. Chain with `take(n)` to get a range.
+    pub fn skip(mut self, n: usize) -> SkippedBuilder<T> {{
+        self.config.start = Some(n as i64);
+        SkippedBuilder {{ config: self.config, _marker: std::marker::PhantomData }}
    }}

-    /// Set the start position. Chain with `take(n)` or `to(end)`.
-    pub fn from(mut self, start: i64) -> FromBuilder<T> {{
-        self.config.start = Some(start);
-        FromBuilder {{ config: self.config, _marker: std::marker::PhantomData }}
-    }}
-
-    /// Set the end position. Chain with `takeLast(n)` or `from(start)`.
-    pub fn to(mut self, end: i64) -> ToBuilder<T> {{
-        self.config.end = Some(end);
-        ToBuilder {{ config: self.config, _marker: std::marker::PhantomData }}
-    }}
-
-    /// Execute the query and return parsed JSON data (all data).
-    pub fn json(self) -> Result<MetricData<T>> {{
+    /// Fetch all data as parsed JSON.
+    pub fn fetch(self) -> Result<MetricData<T>> {{
        self.config.get_json(None)
    }}

-    /// Execute the query and return CSV data as a string (all data).
-    pub fn csv(self) -> Result<String> {{
+    /// Fetch all data as CSV string.
+    pub fn fetch_csv(self) -> Result<String> {{
        self.config.get_text(Some("csv"))
    }}

@@ -266,82 +291,63 @@ impl<T: DeserializeOwned> MetricEndpointBuilder<T> {{
    }}
 }}

-/// Builder after calling `from(start)`. Can chain with `take(n)` or `to(end)`.
-pub struct FromBuilder<T> {{
+/// Builder for single item access.
+pub struct SingleItemBuilder<T> {{
    config: EndpointConfig,
    _marker: std::marker::PhantomData<T>,
 }}

-impl<T: DeserializeOwned> FromBuilder<T> {{
-    /// Take n items from the start position.
-    pub fn take(mut self, n: u64) -> RangeBuilder<T> {{
+impl<T: DeserializeOwned> SingleItemBuilder<T> {{
+    /// Fetch the single item.
+    pub fn fetch(self) -> Result<MetricData<T>> {{
+        self.config.get_json(None)
+    }}
+
+    /// Fetch the single item as CSV.
+    pub fn fetch_csv(self) -> Result<String> {{
+        self.config.get_text(Some("csv"))
+    }}
+}}
+
+/// Builder after calling `skip(n)`. Chain with `take(n)` to specify count.
+pub struct SkippedBuilder<T> {{
+    config: EndpointConfig,
+    _marker: std::marker::PhantomData<T>,
+}}
+
+impl<T: DeserializeOwned> SkippedBuilder<T> {{
+    /// Take n items after the skipped position.
+    pub fn take(mut self, n: usize) -> RangeBuilder<T> {{
        let start = self.config.start.unwrap_or(0);
        self.config.end = Some(start + n as i64);
        RangeBuilder {{ config: self.config, _marker: std::marker::PhantomData }}
    }}

-    /// Set the end position.
-    pub fn to(mut self, end: i64) -> RangeBuilder<T> {{
-        self.config.end = Some(end);
-        RangeBuilder {{ config: self.config, _marker: std::marker::PhantomData }}
-    }}
-
-    /// Execute the query and return parsed JSON data (from start to end of data).
-    pub fn json(self) -> Result<MetricData<T>> {{
+    /// Fetch from the skipped position to the end.
+    pub fn fetch(self) -> Result<MetricData<T>> {{
        self.config.get_json(None)
    }}

-    /// Execute the query and return CSV data as a string.
-    pub fn csv(self) -> Result<String> {{
+    /// Fetch from the skipped position to the end as CSV.
+    pub fn fetch_csv(self) -> Result<String> {{
        self.config.get_text(Some("csv"))
    }}
 }}

-/// Builder after calling `to(end)`. Can chain with `takeLast(n)` or `from(start)`.
-pub struct ToBuilder<T> {{
-    config: EndpointConfig,
-    _marker: std::marker::PhantomData<T>,
-}}
-
-impl<T: DeserializeOwned> ToBuilder<T> {{
-    /// Take last n items before the end position.
-    pub fn take_last(mut self, n: u64) -> RangeBuilder<T> {{
-        let end = self.config.end.unwrap_or(0);
-        self.config.start = Some(end - n as i64);
-        RangeBuilder {{ config: self.config, _marker: std::marker::PhantomData }}
-    }}
-
-    /// Set the start position.
-    pub fn from(mut self, start: i64) -> RangeBuilder<T> {{
-        self.config.start = Some(start);
-        RangeBuilder {{ config: self.config, _marker: std::marker::PhantomData }}
-    }}
-
-    /// Execute the query and return parsed JSON data (from start of data to end).
-    pub fn json(self) -> Result<MetricData<T>> {{
-        self.config.get_json(None)
-    }}
-
-    /// Execute the query and return CSV data as a string.
-    pub fn csv(self) -> Result<String> {{
-        self.config.get_text(Some("csv"))
-    }}
-}}
-
-/// Final builder with range fully specified. Can only call `json()` or `csv()`.
+/// Builder with range fully specified.
 pub struct RangeBuilder<T> {{
    config: EndpointConfig,
    _marker: std::marker::PhantomData<T>,
 }}

 impl<T: DeserializeOwned> RangeBuilder<T> {{
-    /// Execute the query and return parsed JSON data.
-    pub fn json(self) -> Result<MetricData<T>> {{
+    /// Fetch the range as parsed JSON.
+    pub fn fetch(self) -> Result<MetricData<T>> {{
        self.config.get_json(None)
    }}

-    /// Execute the query and return CSV data as a string.
-    pub fn csv(self) -> Result<String> {{
+    /// Fetch the range as CSV string.
+    pub fn fetch_csv(self) -> Result<String> {{
        self.config.get_text(Some("csv"))
    }}
 }}
--- a/crates/brk_bindgen/src/generators/rust/tree.rs
+++ b/crates/brk_bindgen/src/generators/rust/tree.rs
@@ -6,9 +6,8 @@ use std::fmt::Write;
 use brk_types::TreeNode;

 use crate::{
-    ClientMetadata, GenericSyntax, LanguageSyntax, PatternField, RustSyntax, child_type_name,
-    generate_leaf_field, generate_tree_node_field, get_node_fields, get_pattern_instance_base,
-    prepare_tree_node, to_snake_case,
+    ClientMetadata, GenericSyntax, LanguageSyntax, PatternField, RustSyntax,
+    generate_leaf_field, generate_tree_node_field, prepare_tree_node, to_snake_case,
 };

 /// Generate tree structs.
@@ -39,25 +38,29 @@ fn generate_tree_node(
        return;
    };

+    // Generate struct definition
    writeln!(output, "/// Metrics tree node.").unwrap();
    writeln!(output, "pub struct {} {{", name).unwrap();

-    for ((field, child_fields), (child_name, _)) in
-        ctx.fields_with_child_info.iter().zip(ctx.children.iter())
-    {
-        let field_name = to_snake_case(&field.name);
-        let type_annotation = metadata.resolve_tree_field_type(
-            field,
-            child_fields.as_deref(),
-            name,
-            child_name,
-            GenericSyntax::RUST,
-        );
+    for child in &ctx.children {
+        let field_name = to_snake_case(child.name);
+        let type_annotation = if child.should_inline {
+            child.inline_type_name.clone()
+        } else {
+            metadata.resolve_tree_field_type(
+                &child.field,
+                child.child_fields.as_deref(),
+                name,
+                child.name,
+                GenericSyntax::RUST,
+            )
+        };
        writeln!(output, "    pub {}: {},", field_name, type_annotation).unwrap();
    }

    writeln!(output, "}}\n").unwrap();

+    // Generate impl block
    writeln!(output, "impl {} {{", name).unwrap();
    writeln!(
        output,
@@ -67,53 +70,40 @@ fn generate_tree_node(
    writeln!(output, "        Self {{").unwrap();

    let syntax = RustSyntax;
-    for ((field_info, child_fields), (child_name, child_node)) in
-        ctx.fields_with_child_info.iter().zip(ctx.children.iter())
-    {
-        let field_name = to_snake_case(&field_info.name);
+    for child in &ctx.children {
+        let field_name = to_snake_case(child.name);

-        // Check if this is a pattern type and if it's parameterizable
-        let is_parameterizable = child_fields
-            .as_ref()
-            .is_some_and(|cf| metadata.is_parameterizable_fields(cf));
-
-        if metadata.is_pattern_type(&field_info.rust_type) && is_parameterizable {
-            // Parameterizable pattern: use pattern constructor with metric base
-            let pattern_base = get_pattern_instance_base(child_node);
-            generate_tree_node_field(
-                output,
-                &syntax,
-                field_info,
-                metadata,
-                "            ",
-                child_name,
-                Some(&pattern_base),
-            );
-        } else if child_fields.is_some() {
-            // Non-parameterizable pattern or regular branch: use inline struct
-            let child_struct = child_type_name(name, child_name);
-            let path_expr = syntax.path_expr("base_path", &format!("_{}", child_name));
+        if child.is_leaf {
+            if let TreeNode::Leaf(leaf) = child.node {
+                generate_leaf_field(
+                    output,
+                    &syntax,
+                    "client.clone()",
+                    child.name,
+                    leaf,
+                    metadata,
+                    "            ",
+                );
+            }
+        } else if child.should_inline {
+            // Inline struct
+            let path_expr = syntax.path_expr("base_path", &format!("_{}", child.name));
            writeln!(
                output,
                "            {}: {}::new(client.clone(), {}),",
-                field_name, child_struct, path_expr
+                field_name, child.inline_type_name, path_expr
            )
            .unwrap();
-        } else if let TreeNode::Leaf(leaf) = child_node {
-            // Leaf field - use shared helper
-            generate_leaf_field(
+        } else {
+            // Use pattern constructor
+            generate_tree_node_field(
                output,
                &syntax,
-                "client.clone()",
-                child_name,
-                leaf,
+                &child.field,
                metadata,
                "            ",
-            );
-        } else {
-            panic!(
-                "Field '{}' is a leaf with no TreeNode::Leaf. This shouldn't happen.",
-                field_info.name
+                child.name,
+                Some(&child.base_result.base),
            );
        }
    }
@@ -122,21 +112,17 @@ fn generate_tree_node(
    writeln!(output, "    }}").unwrap();
    writeln!(output, "}}\n").unwrap();

-    for (child_name, child_node) in ctx.children {
-        if let TreeNode::Branch(grandchildren) = child_node {
-            let child_fields = get_node_fields(grandchildren, pattern_lookup);
-            // Generate child struct if no pattern match OR pattern is not parameterizable
-            if !metadata.is_parameterizable_fields(&child_fields) {
-                let child_struct = child_type_name(name, child_name);
-                generate_tree_node(
-                    output,
-                    &child_struct,
-                    child_node,
-                    pattern_lookup,
-                    metadata,
-                    generated,
-                );
-            }
+    // Generate child structs
+    for child in &ctx.children {
+        if child.should_inline {
+            generate_tree_node(
+                output,
+                &child.inline_type_name,
+                child.node,
+                pattern_lookup,
+                metadata,
+                generated,
+            );
        }
    }
 }
--- a/crates/brk_cli/Cargo.toml
+++ b/crates/brk_cli/Cargo.toml
@@ -23,7 +23,7 @@ brk_rpc = { workspace = true }
 brk_server = { workspace = true }
 clap = { version = "4.5.54", features = ["derive", "string"] }
 color-eyre = { workspace = true }
-importmap = "0.1.2"
+importmap = "0.1.3"
 # importmap = { path = "../../../importmap" }
 tracing = { workspace = true }
 minreq = { workspace = true }
--- a/crates/brk_cli/src/main.rs
+++ b/crates/brk_cli/src/main.rs
@@ -17,6 +17,7 @@ use brk_mempool::Mempool;
 use brk_query::AsyncQuery;
 use brk_reader::Reader;
 use brk_server::{Server, VERSION};
+use importmap::ImportMap;
 use tracing::info;
 use vecdb::Exit;

@@ -85,25 +86,28 @@ pub fn run() -> color_eyre::Result<()> {
    let data_path = config.brkdir();

    let future = async move {
-        let bundle_path = if website.is_some() {
-            // Try to find local dev directories - check cwd and parent directories
-            let find_dev_dirs = || -> Option<(PathBuf, PathBuf)> {
-                let mut dir = std::env::current_dir().ok()?;
-                loop {
-                    let websites = dir.join("websites");
-                    let modules = dir.join("modules");
-                    if websites.exists() && modules.exists() {
-                        return Some((websites, modules));
-                    }
-                    // Stop at workspace root (crates/ indicates we're there)
-                    if dir.join("crates").exists() {
-                        return None;
-                    }
-                    dir = dir.parent()?.to_path_buf();
+        // Try to find local dev directories - check cwd and parent directories
+        let find_dev_dirs = || -> Option<(PathBuf, PathBuf)> {
+            let mut dir = std::env::current_dir().ok()?;
+            loop {
+                let websites = dir.join("websites");
+                let modules = dir.join("modules");
+                if websites.exists() && modules.exists() {
+                    return Some((websites, modules));
                }
-            };
+                // Stop at workspace root (crates/ indicates we're there)
+                if dir.join("crates").exists() {
+                    return None;
+                }
+                dir = dir.parent()?.to_path_buf();
+            }
+        };

-            let websites_path = if let Some((websites, _modules)) = find_dev_dirs() {
+        let dev_dirs = find_dev_dirs();
+        let is_dev = dev_dirs.is_some();
+
+        let bundle_path = if website.is_some() {
+            let websites_path = if let Some((websites, _modules)) = dev_dirs {
                websites
            } else {
                let downloaded_brk_path = downloads_path.join(format!("brk-{VERSION}"));
@@ -133,19 +137,28 @@ pub fn run() -> color_eyre::Result<()> {
            None
        };

-        // Generate import map for cache busting
+        // Generate import map for cache busting (disabled in dev mode)
        if let Some(ref path) = bundle_path {
-            match importmap::ImportMap::scan(path, "") {
-                Ok(map) => {
-                    let html_path = path.join("index.html");
-                    if let Ok(html) = fs::read_to_string(&html_path)
-                        && let Some(updated) = map.update_html(&html)
-                    {
-                        let _ = fs::write(&html_path, updated);
-                        info!("Updated importmap in index.html");
+            let map = if is_dev {
+                ImportMap::empty()
+            } else {
+                match ImportMap::scan(path, "") {
+                    Ok(map) => map,
+                    Err(e) => {
+                        tracing::error!("Failed to generate importmap: {e}");
+                        ImportMap::empty()
                    }
                }
-                Err(e) => tracing::error!("Failed to generate importmap: {e}"),
+            };
+
+            let html_path = path.join("index.html");
+            if let Ok(html) = fs::read_to_string(&html_path)
+                && let Some(updated) = map.update_html(&html)
+            {
+                let _ = fs::write(&html_path, updated);
+                if !is_dev {
+                    info!("Updated importmap in index.html");
+                }
            }
        }

--- a/crates/brk_client/examples/basic.rs
+++ b/crates/brk_client/examples/basic.rs
@@ -14,6 +14,7 @@ fn main() -> brk_client::Result<()> {
    });

    // Fetch price data using the typed metrics API
+    // Using new idiomatic API: last(3).fetch()
    let price_close = client
        .metrics()
        .price
@@ -22,8 +23,8 @@ fn main() -> brk_client::Result<()> {
        .close
        .by
        .dateindex()
-        .from(-3)
-        .json()?;
+        .last(3)
+        .fetch()?;
    println!("Last 3 price close values: {:?}", price_close);

    // Fetch block data
@@ -35,12 +36,11 @@ fn main() -> brk_client::Result<()> {
        .sum
        .by
        .dateindex()
-        .from(-3)
-        .json()?;
+        .last(3)
+        .fetch()?;
    println!("Last 3 block count values: {:?}", block_count);

    // Fetch supply data
-    //
    dbg!(
        client
            .metrics()
@@ -58,8 +58,8 @@ fn main() -> brk_client::Result<()> {
        .bitcoin
        .by
        .dateindex()
-        .from(-3)
-        .csv()?;
+        .last(3)
+        .fetch_csv()?;
    println!("Last 3 circulating supply values: {:?}", circulating);

    // Using generic metric fetching
--- a/crates/brk_client/src/lib.rs
+++ b/crates/brk_client/src/lib.rs
--- a/crates/brk_computer/examples/computer_read.rs
+++ b/crates/brk_computer/examples/computer_read.rs
@@ -1,10 +1,10 @@
-use std::{env, path::Path, thread};
+use std::{env, path::Path, thread, time::Instant};

 use brk_computer::Computer;
 use brk_error::Result;
 use brk_fetcher::Fetcher;
 use brk_indexer::Indexer;
-use vecdb::{AnyStoredVec, Exit};
+use vecdb::{AnySerializableVec, AnyVec, Exit};

 pub fn main() -> Result<()> {
    // Can't increase main thread's stack size, thus we need to use another thread
@@ -19,7 +19,6 @@ fn run() -> Result<()> {
    brk_logger::init(None)?;

    let outputs_dir = Path::new(&env::var("HOME").unwrap()).join(".brk");
-    // let outputs_dir = Path::new("../../_outputs");

    let indexer = Indexer::forced_import(&outputs_dir)?;

@@ -30,7 +29,35 @@ fn run() -> Result<()> {

    let computer = Computer::forced_import(&outputs_dir, &indexer, Some(fetcher))?;

-    let _a = dbg!(computer.transactions.fees.fee.base.region().meta());
+    // Test emptyaddressdata (underlying BytesVec) - direct access
+    let empty_data = &computer.distribution.addresses_data.empty;
+    println!("emptyaddressdata (BytesVec) len: {}", empty_data.len());
+
+    let start = Instant::now();
+    let mut buf = Vec::new();
+    empty_data.write_json(Some(empty_data.len() - 1), Some(empty_data.len()), &mut buf)?;
+    println!("emptyaddressdata last item JSON: {}", String::from_utf8_lossy(&buf));
+    println!("Time for BytesVec write_json: {:?}", start.elapsed());
+
+    // Test emptyaddressindex (LazyVecFrom1 wrapper) - computed access
+    let empty_index = &computer.distribution.emptyaddressindex;
+    println!("\nemptyaddressindex (LazyVecFrom1) len: {}", empty_index.len());
+
+    let start = Instant::now();
+    let mut buf = Vec::new();
+    empty_index.write_json(Some(empty_index.len() - 1), Some(empty_index.len()), &mut buf)?;
+    println!("emptyaddressindex last item JSON: {}", String::from_utf8_lossy(&buf));
+    println!("Time for LazyVecFrom1 write_json: {:?}", start.elapsed());
+
+    // Compare with loaded versions
+    let loaded_data = &computer.distribution.addresses_data.loaded;
+    println!("\nloadedaddressdata (BytesVec) len: {}", loaded_data.len());
+
+    let start = Instant::now();
+    let mut buf = Vec::new();
+    loaded_data.write_json(Some(loaded_data.len() - 1), Some(loaded_data.len()), &mut buf)?;
+    println!("loadedaddressdata last item JSON: {}", String::from_utf8_lossy(&buf));
+    println!("Time for BytesVec write_json: {:?}", start.elapsed());

    Ok(())
 }
--- a/crates/brk_error/src/lib.rs
+++ b/crates/brk_error/src/lib.rs
@@ -137,6 +137,18 @@ pub enum Error {


 impl Error {
+    /// Returns true if this error is due to a file lock (another process has the database open).
+    /// Lock errors are transient and should not trigger data deletion.
+    pub fn is_lock_error(&self) -> bool {
+        matches!(self, Error::VecDB(e) if e.is_lock_error())
+    }
+
+    /// Returns true if this error indicates data corruption or version incompatibility.
+    /// These errors may require resetting/deleting the data to recover.
+    pub fn is_data_error(&self) -> bool {
+        matches!(self, Error::VecDB(e) if e.is_data_error())
+    }
+
    /// Returns true if this network/fetch error indicates a permanent/blocking condition
    /// that won't be resolved by retrying (e.g., DNS failure, connection refused, blocked endpoint).
    /// Returns false for transient errors worth retrying (timeouts, rate limits, server errors).
--- a/crates/brk_indexer/src/lib.rs
+++ b/crates/brk_indexer/src/lib.rs
@@ -47,27 +47,26 @@ impl Indexer {
        let indexed_path = outputs_dir.join("indexed");

        let try_import = || -> Result<Self> {
-            let (vecs, stores) = thread::scope(|s| -> Result<_> {
-                let vecs = s.spawn(|| -> Result<_> {
-                    let i = Instant::now();
-                    let vecs = Vecs::forced_import(&indexed_path, VERSION)?;
-                    info!("Imported vecs in {:?}", i.elapsed());
-                    Ok(vecs)
-                });
+            let i = Instant::now();
+            let vecs = Vecs::forced_import(&indexed_path, VERSION)?;
+            info!("Imported vecs in {:?}", i.elapsed());

-                let i = Instant::now();
-                let stores = Stores::forced_import(&indexed_path, VERSION)?;
-                info!("Imported stores in {:?}", i.elapsed());
-
-                Ok((vecs.join().unwrap()?, stores))
-            })?;
+            let i = Instant::now();
+            let stores = Stores::forced_import(&indexed_path, VERSION)?;
+            info!("Imported stores in {:?}", i.elapsed());

            Ok(Self { vecs, stores })
        };

        match try_import() {
            Ok(result) => Ok(result),
-            Err(err) if can_retry => {
+            Err(err) if err.is_lock_error() => {
+                // Lock errors are transient - another process has the database open.
+                // Don't delete data, just return the error.
+                Err(err)
+            }
+            Err(err) if can_retry && err.is_data_error() => {
+                // Data corruption or version mismatch - safe to delete and retry
                info!("{err:?}, deleting {indexed_path:?} and retrying");
                fs::remove_dir_all(&indexed_path)?;
                Self::forced_import_inner(outputs_dir, false)
--- a/modules/brk-client/index.js
+++ b/modules/brk-client/index.js
--- a/modules/brk-client/package.json
+++ b/modules/brk-client/package.json
@@ -2,6 +2,10 @@
  "bugs": {
    "url": "https://github.com/bitcoinresearchkit/brk/issues"
  },
+  "scripts": {
+    "test": "node tests/basic.js",
+    "test:tree": "node tests/tree.js"
+  },
  "description": "BRK JavaScript client",
  "engines": {
    "node": ">=18"
--- a/modules/brk-client/tests/basic.js
+++ b/modules/brk-client/tests/basic.js
@@ -1,5 +1,74 @@
 import { BrkClient } from "../index.js";

-let client = new BrkClient("http://localhost:3110");
+const client = new BrkClient("http://localhost:3110");

-let blocks = await client.getBlocks();
+console.log("Testing idiomatic API...\n");
+
+// Test getter access (property)
+console.log("1. Getter access (.by.dateindex):");
+const all = await client.metrics.price.usd.split.close.by.dateindex;
+console.log(`   Total: ${all.total}, Got: ${all.data.length} items\n`);
+
+// Test dynamic access (bracket notation)
+console.log("2. Dynamic access (.by['dateindex']):");
+const allDynamic = await client.metrics.price.usd.split.close.by["dateindex"];
+console.log(
+  `   Total: ${allDynamic.total}, Got: ${allDynamic.data.length} items\n`,
+);
+
+// Test fetch all (explicit .fetch())
+console.log("3. Explicit .fetch():");
+const allExplicit =
+  await client.metrics.price.usd.split.close.by.dateindex.fetch();
+console.log(
+  `   Total: ${allExplicit.total}, Got: ${allExplicit.data.length} items\n`,
+);
+
+// Test first(n)
+console.log("4. First 5 items (.first(5)):");
+const first5 = await client.metrics.price.usd.split.close.by.dateindex.first(5);
+console.log(
+  `   Total: ${first5.total}, Start: ${first5.start}, End: ${first5.end}, Got: ${first5.data.length} items\n`,
+);
+
+// Test last(n)
+console.log("5. Last 5 items (.last(5)):");
+const last5 = await client.metrics.price.usd.split.close.by.dateindex.last(5);
+console.log(
+  `   Total: ${last5.total}, Start: ${last5.start}, End: ${last5.end}, Got: ${last5.data.length} items\n`,
+);
+
+// Test slice(start, end)
+console.log("6. Slice 10-20 (.slice(10, 20)):");
+const sliced = await client.metrics.price.usd.split.close.by.dateindex.slice(
+  10,
+  20,
+);
+console.log(
+  `   Total: ${sliced.total}, Start: ${sliced.start}, End: ${sliced.end}, Got: ${sliced.data.length} items\n`,
+);
+
+// Test get(index) - single item
+console.log("7. Single item (.get(100)):");
+const single = await client.metrics.price.usd.split.close.by.dateindex.get(100);
+console.log(
+  `   Total: ${single.total}, Start: ${single.start}, End: ${single.end}, Got: ${single.data.length} item(s)\n`,
+);
+
+// Test skip(n).take(m) chaining
+console.log("8. Skip and take (.skip(100).take(10)):");
+const skipTake = await client.metrics.price.usd.split.close.by.dateindex
+  .skip(100)
+  .take(10);
+console.log(
+  `   Total: ${skipTake.total}, Start: ${skipTake.start}, End: ${skipTake.end}, Got: ${skipTake.data.length} items\n`,
+);
+
+// Test fetchCsv
+console.log("9. Fetch as CSV (.last(3).fetchCsv()):");
+const csv = await client.metrics.price.usd.split.close.by.dateindex
+  .last(3)
+  .fetchCsv();
+console.log(`   CSV preview: ${csv.substring(0, 100)}...\n`);
+
+console.log("All tests passed!");
--- a/modules/brk-client/tests/tree.js
+++ b/modules/brk-client/tests/tree.js
@@ -6,9 +6,9 @@ import { BrkClient } from "../index.js";

 /**
 * Recursively collect all metric patterns from the tree.
- * @param {object} obj
+ * @param {Record<string, any>} obj
 * @param {string} path
- * @returns {Array<{path: string, metric: object, indexes: string[]}>}
+ * @returns {Array<{path: string, metric: Record<string, any>, indexes: string[]}>}
 */
 function getAllMetrics(obj, path = "") {
  const metrics = [];
@@ -21,10 +21,10 @@ function getAllMetrics(obj, path = "") {

    const currentPath = path ? `${path}.${key}` : key;

-    // Check if this is a metric pattern (has 'by' property with index methods)
+    // Check if this is a metric pattern (has 'by' property with index getters)
    if (attr.by && typeof attr.by === "object") {
      const indexes = Object.keys(attr.by).filter(
-        (k) => !k.startsWith("_") && typeof attr.by[k] === "function",
+        (k) => !k.startsWith("_") && typeof attr.by[k] === "object",
      );
      if (indexes.length > 0) {
        metrics.push({ path: currentPath, metric: attr, indexes });
@@ -41,54 +41,38 @@ function getAllMetrics(obj, path = "") {
 }

 async function testAllEndpoints() {
-  const client = new BrkClient("http://localhost:3110");
+  const client = new BrkClient({ baseUrl: "http://localhost:3110", timeout: 15000 });

-  const metrics = getAllMetrics(client.tree);
+  const metrics = getAllMetrics(client.metrics);
  console.log(`\nFound ${metrics.length} metrics`);

  let success = 0;
-  let failed = 0;
-  const errors = [];

  for (const { path, metric, indexes } of metrics) {
    for (const idxName of indexes) {
      try {
-        const endpoint = metric.by[idxName]();
-        const res = await endpoint.range(-3);
+        const endpoint = metric.by[idxName];
+        const res = await endpoint.last(1);
        const count = res.data.length;
-        if (count !== 3) {
-          failed++;
-          const errorMsg = `FAIL: ${path}.by.${idxName}() -> expected 3, got ${count}`;
-          errors.push(errorMsg);
-          console.log(errorMsg);
-        } else {
-          success++;
-          console.log(`OK: ${path}.by.${idxName}() -> ${count} items`);
+        if (count !== 1) {
+          console.log(
+            `FAIL: ${path}.by.${idxName} -> expected 1, got ${count}`,
+          );
+          return;
        }
+        success++;
+        console.log(`OK: ${path}.by.${idxName} -> ${count} items`);
      } catch (e) {
-        failed++;
-        const errorMsg = `FAIL: ${path}.by.${idxName}() -> ${e.message}`;
-        errors.push(errorMsg);
-        console.log(errorMsg);
+        console.log(
+          `FAIL: ${path}.by.${idxName} -> ${e instanceof Error ? e.message : e}`,
+        );
+        return;
      }
    }
  }

  console.log(`\n=== Results ===`);
  console.log(`Success: ${success}`);
-  console.log(`Failed: ${failed}`);
-
-  if (errors.length > 0) {
-    console.log(`\nErrors:`);
-    errors.slice(0, 10).forEach((err) => console.log(`  ${err}`));
-    if (errors.length > 10) {
-      console.log(`  ... and ${errors.length - 10} more`);
-    }
-  }
-
-  if (failed > 0) {
-    process.exit(1);
-  }
 }

 testAllEndpoints();
--- a/packages/brk_client/brk_client/init.py
+++ b/packages/brk_client/brk_client/init.py
--- a/packages/brk_client/tests/basic.py
+++ b/packages/brk_client/tests/basic.py
@@ -36,29 +36,30 @@ def test_fetch_csv_metric():

 def test_fetch_typed_metric():
    client = BrkClient("http://localhost:3110")
-    a = client.metrics.constants.constant_0.by.dateindex().from_(-10).json()
+    # Using new idiomatic API: tail(10).fetch() or [-10:].fetch()
+    a = client.metrics.constants.constant_0.by.dateindex().tail(10).fetch()
    print(a)
-    b = client.metrics.outputs.count.utxo_count.by.height().from_(-10).json()
+    b = client.metrics.outputs.count.utxo_count.by.height().tail(10).fetch()
    print(b)
-    c = client.metrics.price.usd.split.close.by.dateindex().from_(-10).json()
+    c = client.metrics.price.usd.split.close.by.dateindex().tail(10).fetch()
    print(c)
    d = (
        client.metrics.market.dca.period_lump_sum_stack._10y.dollars.by.dateindex()
-        .from_(-10)
-        .json()
+        .tail(10)
+        .fetch()
    )
    print(d)
    e = (
        client.metrics.market.dca.class_average_price._2017.by.dateindex()
-        .from_(-10)
-        .json()
+        .tail(10)
+        .fetch()
    )
    print(e)
    f = (
        client.metrics.distribution.address_cohorts.amount_range._10k_sats_to_100k_sats.activity.sent.dollars.cumulative.by.dateindex()
-        .from_(-10)
-        .json()
+        .tail(10)
+        .fetch()
    )
    print(f)
-    g = client.metrics.price.usd.ohlc.by.dateindex().from_(-10).json()
+    g = client.metrics.price.usd.ohlc.by.dateindex().tail(10).fetch()
    print(g)
--- a/packages/brk_client/tests/tree.py
+++ b/packages/brk_client/tests/tree.py
@@ -41,7 +41,7 @@ def test_all_endpoints():
    """Test fetching last 3 values from all metric endpoints."""
    client = BrkClient("http://localhost:3110")

-    metrics = get_all_metrics(client.tree)
+    metrics = get_all_metrics(client.metrics)
    print(f"\nFound {len(metrics)} metrics")

    success = 0
@@ -53,7 +53,8 @@ def test_all_endpoints():
            try:
                by = metric.by
                endpoint = getattr(by, idx_name)()
-                res = endpoint.range(-3)
+                # Use the new idiomatic API: tail(3).fetch() or [-3:].fetch()
+                res = endpoint.tail(3).fetch()
                count = len(res["data"])
                if count != 3:
                    failed += 1
--- a/websites/bitview/index.html
+++ b/websites/bitview/index.html
@@ -1515,148 +1515,7 @@
    </style>

    <!-- IMPORTMAP -->
-    <script type="importmap">
-    {
-      "imports": {
-        "/scripts/chart/index.js": "/scripts/chart/index.024e5d6b.js",
-        "/scripts/chart/oklch.js": "/scripts/chart/oklch.21450255.js",
-        "/scripts/entry.js": "/scripts/entry.93446a1b.js",
-        "/scripts/lazy.js": "/scripts/lazy.1ae52534.js",
-        "/scripts/main.js": "/scripts/main.22a5bd79.js",
-        "/scripts/modules/brk-client/index.js": "/scripts/modules/brk-client/index.664c39c8.js",
-        "/scripts/modules/brk-client/tests/basic.js": "/scripts/modules/brk-client/tests/basic.b92ff866.js",
-        "/scripts/modules/brk-client/tests/tree.js": "/scripts/modules/brk-client/tests/tree.ba9474f7.js",
-        "/scripts/modules/lean-qr/2.6.1/index.mjs": "/scripts/modules/lean-qr/2.6.1/index.09195c13.mjs",
-        "/scripts/modules/leeoniya-ufuzzy/1.0.19/dist/uFuzzy.mjs": "/scripts/modules/leeoniya-ufuzzy/1.0.19/dist/uFuzzy.803b7fb0.mjs",
-        "/scripts/modules/lightweight-charts/5.0.9/dist/lightweight-charts.standalone.production.mjs": "/scripts/modules/lightweight-charts/5.0.9/dist/lightweight-charts.standalone.production.1e264451.mjs",
-        "/scripts/modules/lightweight-charts/5.1.0/dist/lightweight-charts.standalone.production.mjs": "/scripts/modules/lightweight-charts/5.1.0/dist/lightweight-charts.standalone.production.5c2a821a.mjs",
-        "/scripts/modules/modern-screenshot/4.6.6/dist/index.mjs": "/scripts/modules/modern-screenshot/4.6.6/dist/index.0f951334.mjs",
-        "/scripts/modules/modern-screenshot/4.6.7/dist/index.js": "/scripts/modules/modern-screenshot/4.6.7/dist/index.070574d6.js",
-        "/scripts/modules/modern-screenshot/4.6.7/dist/index.mjs": "/scripts/modules/modern-screenshot/4.6.7/dist/index.e9e389fe.mjs",
-        "/scripts/modules/modern-screenshot/4.6.7/dist/worker.js": "/scripts/modules/modern-screenshot/4.6.7/dist/worker.1265d9cd.js",
-        "/scripts/modules/solidjs-signals/0.6.3/dist/prod.js": "/scripts/modules/solidjs-signals/0.6.3/dist/prod.2f80e335.js",
-        "/scripts/modules/solidjs-signals/0.8.5/dist/prod.js": "/scripts/modules/solidjs-signals/0.8.5/dist/prod.8ae56250.js",
-        "/scripts/options/_partial_old.js": "/scripts/options/_partial_old.62bf3faa.js",
-        "/scripts/options/chain.js": "/scripts/options/chain.c173ace8.js",
-        "/scripts/options/cohorts/address.js": "/scripts/options/cohorts/address.2e8a42cb.js",
-        "/scripts/options/cohorts/data.js": "/scripts/options/cohorts/data.11381d83.js",
-        "/scripts/options/cohorts/index.js": "/scripts/options/cohorts/index.b0e57c9d.js",
-        "/scripts/options/cohorts/shared.js": "/scripts/options/cohorts/shared.87b9837c.js",
-        "/scripts/options/cohorts/utxo.js": "/scripts/options/cohorts/utxo.f0e69857.js",
-        "/scripts/options/cointime.js": "/scripts/options/cointime.e25633d9.js",
-        "/scripts/options/colors/cohorts.js": "/scripts/options/colors/cohorts.262d4551.js",
-        "/scripts/options/colors/index.js": "/scripts/options/colors/index.a54dc83f.js",
-        "/scripts/options/colors/misc.js": "/scripts/options/colors/misc.bee7dbee.js",
-        "/scripts/options/constants.js": "/scripts/options/constants.16dfce27.js",
-        "/scripts/options/context.js": "/scripts/options/context.8bf2932e.js",
-        "/scripts/options/full.js": "/scripts/options/full.11772605.js",
-        "/scripts/options/market/averages.js": "/scripts/options/market/averages.d95aa3e1.js",
-        "/scripts/options/market/index.js": "/scripts/options/market/index.e3b750d6.js",
-        "/scripts/options/market/indicators/bands.js": "/scripts/options/market/indicators/bands.81b19b83.js",
-        "/scripts/options/market/indicators/index.js": "/scripts/options/market/indicators/index.70e9b3e4.js",
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-        "/scripts/options/market/indicators/onchain.js": "/scripts/options/market/indicators/onchain.f75ddfd9.js",
-        "/scripts/options/market/indicators/volatility.js": "/scripts/options/market/indicators/volatility.08ec92d7.js",
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-        "/scripts/panes/nav.js": "/scripts/panes/nav.0338dc4b.js",
-        "/scripts/panes/search.js": "/scripts/panes/search.0338dc4b.js",
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+
    <!-- /IMPORTMAP -->

    <!-- ------- -->
--- a/websites/bitview/scripts/chart/index.js
+++ b/websites/bitview/scripts/chart/index.js
@@ -19,6 +19,7 @@ import { throttle } from "../utils/timing.js";
 import { serdeBool } from "../utils/serde.js";
 import { stringToId } from "../utils/format.js";
 import { style } from "../utils/elements.js";
+import { resources } from "../resources.js";

 /**
 * @typedef {Object} Valued
@@ -70,20 +71,18 @@ const lineWidth = /** @type {any} */ (1.5);
 * @param {HTMLElement} args.parent
 * @param {Signals} args.signals
 * @param {Colors} args.colors
- * @param {Resources} args.resources
 * @param {BrkClient} args.brk
 * @param {Accessor<ChartableIndex>} args.index
 * @param {((unknownTimeScaleCallback: VoidFunction) => void)} [args.timeScaleSetCallback]
 * @param {true} [args.fitContent]
 * @param {{unit: Unit; blueprints: AnySeriesBlueprint[]}[]} [args.config]
 */
-function createChartElement({
+export function createChartElement({
  parent,
  signals,
  colors,
  id: chartId,
  index,
-  resources,
  brk,
  timeScaleSetCallback,
  fitContent,
@@ -1076,5 +1075,3 @@ function numberToUSFormat(value, digits, options) {
 * @typedef {typeof createChartElement} CreateChartElement
 * @typedef {ReturnType<createChartElement>} Chart
 */
-
-export default { createChartElement };
--- a/websites/bitview/scripts/entry.js
+++ b/websites/bitview/scripts/entry.js
@@ -6,7 +6,7 @@
 * @import { Signal, Signals, Accessor } from "./signals.js";
 *
 * @import * as Brk from "./modules/brk-client/index.js"
- * @import { BrkClient} from "./modules/brk-client/index.js"
+ * @import { BrkClient, Index, Metric, MetricData } from "./modules/brk-client/index.js"
 *
 * @import { Resources, MetricResource } from './resources.js'
 *
@@ -28,23 +28,91 @@
 // import uFuzzy = require("./modules/leeoniya-ufuzzy/1.0.19/dist/uFuzzy.d.ts");

 /**
- * @typedef {typeof import("./lazy")["default"]} Modules
 * @typedef {[number, number, number, number]} OHLCTuple
+ *
+ * Brk type aliases
+ * @typedef {Brk.MetricsTree_Distribution_UtxoCohorts} UtxoCohortTree
+ * @typedef {Brk.MetricsTree_Distribution_AddressCohorts} AddressCohortTree
+ * @typedef {Brk.MetricsTree_Distribution_UtxoCohorts_All} AllUtxoPattern
+ * @typedef {Brk.MetricsTree_Distribution_UtxoCohorts_Term_Short} ShortTermPattern
+ * @typedef {Brk.MetricsTree_Distribution_UtxoCohorts_Term_Long} LongTermPattern
+ * @typedef {Brk._10yPattern} MaxAgePattern
+ * @typedef {Brk._10yTo12yPattern} AgeRangePattern
+ * @typedef {Brk._0satsPattern2} UtxoAmountPattern
+ * @typedef {Brk._0satsPattern} AddressAmountPattern
+ * @typedef {Brk._100btcPattern} BasicUtxoPattern
+ * @typedef {Brk._0satsPattern2} EpochPattern
+ * @typedef {Brk.Ratio1ySdPattern} Ratio1ySdPattern
+ * @typedef {Brk.Dollars} Dollars
+ * @typedef {Brk.Price111dSmaPattern} EmaRatioPattern
+ * @typedef {Brk.CoinbasePattern} CoinbasePattern
+ * @typedef {Brk.ActivePriceRatioPattern} ActivePriceRatioPattern
+ * @typedef {Brk.UnclaimedRewardsPattern} ValuePattern
+ * @typedef {Brk.AnyMetricPattern} AnyMetricPattern
+ * @typedef {Brk.AnyMetricEndpointBuilder} AnyMetricEndpoint
+ * @typedef {Brk.AnyMetricData} AnyMetricData
+ * @typedef {Brk.AddrCountPattern} AddrCountPattern
+ * @typedef {Brk.MetricsTree_Blocks_Interval} IntervalPattern
+ * @typedef {Brk.MetricsTree_Supply_Circulating} SupplyPattern
+ * @typedef {Brk.RelativePattern} GlobalRelativePattern
+ * @typedef {Brk.RelativePattern2} OwnRelativePattern
+ * @typedef {Brk.RelativePattern5} FullRelativePattern
+ * @typedef {Brk.MetricsTree_Distribution_UtxoCohorts_All_Relative} AllRelativePattern
+ */
+
+/**
+ * @template T
+ * @typedef {Brk.BlockCountPattern<T>} BlockCountPattern
+ */
+/**
+ * @template T
+ * @typedef {Brk.FullnessPattern<T>} FullnessPattern
+ */
+/**
+ * @template T
+ * @typedef {Brk.FeeRatePattern<T>} FeeRatePattern
+ */
+/**
+ * @template T
+ * @typedef {Brk.MetricEndpointBuilder<T>} MetricEndpoint
+ */
+/**
+ * @template T
+ * @typedef {Brk.DollarsPattern<T>} SizePattern
+ */
+/**
+ * @template T
+ * @typedef {Brk.CountPattern2<T>} CountStatsPattern
+ */
+/**
+ * @typedef {Brk.MetricsTree_Blocks_Size} BlockSizePattern
+ */
+/**
+ * Stats pattern union - accepts both CountStatsPattern and BlockSizePattern
+ * @typedef {CountStatsPattern<any> | BlockSizePattern} AnyStatsPattern
+ */
+
+/**
 *
 * @typedef {InstanceType<typeof BrkClient>["INDEXES"]} Indexes
 * @typedef {Indexes[number]} IndexName
 * @typedef {InstanceType<typeof BrkClient>["POOL_ID_TO_POOL_NAME"]} PoolIdToPoolName
 * @typedef {keyof PoolIdToPoolName} PoolId
 *
+ * Tree branch types
+ * @typedef {Brk.MetricsTree_Market} Market
+ * @typedef {Brk.MetricsTree_Market_MovingAverage} MarketMovingAverage
+ * @typedef {Brk.MetricsTree_Market_Dca} MarketDca
+ *
 * Pattern unions by cohort type
 * @typedef {AllUtxoPattern | AgeRangePattern | UtxoAmountPattern} UtxoCohortPattern
 * @typedef {AddressAmountPattern} AddressCohortPattern
 * @typedef {UtxoCohortPattern | AddressCohortPattern} CohortPattern
 *
 * Relative pattern capability types
- * @typedef {RelativePattern | RelativePattern5} RelativeWithMarketCap
- * @typedef {RelativePattern2 | RelativePattern5} RelativeWithOwnMarketCap
- * @typedef {RelativePattern2 | RelativePattern5 | AllRelativePattern} RelativeWithOwnPnl
+ * @typedef {GlobalRelativePattern | FullRelativePattern} RelativeWithMarketCap
+ * @typedef {OwnRelativePattern | FullRelativePattern} RelativeWithOwnMarketCap
+ * @typedef {OwnRelativePattern | FullRelativePattern | AllRelativePattern} RelativeWithOwnPnl
 *
 * Capability-based pattern groupings (patterns that have specific properties)
 * @typedef {AllUtxoPattern | AgeRangePattern | UtxoAmountPattern} PatternWithRealizedPrice
--- a/websites/bitview/scripts/lazy.js
+++ b/websites/bitview/scripts/lazy.js
@@ -1,53 +0,0 @@
-const imports = {
-  async signals() {
-    return import("./signals.js").then((d) => d.default);
-  },
-  async leanQr() {
-    return import("./modules/lean-qr/2.6.1/index.mjs").then((d) => d);
-  },
-  async ufuzzy() {
-    return import("./modules/leeoniya-ufuzzy/1.0.19/dist/uFuzzy.mjs").then(
-      ({ default: d }) => d,
-    );
-  },
-  async brkClient() {
-    return import("./modules/brk-client/index.js").then((d) => d);
-  },
-  async resources() {
-    return import("./resources.js").then((d) => d);
-  },
-
-  async chart() {
-    return window.document.fonts.ready.then(() =>
-      import("./chart/index.js").then((d) => d.default),
-    );
-  },
-  async options() {
-    return import("./options/full.js").then((d) => d);
-  },
-};
-
-/**
- * @template {keyof typeof imports} K
- * @param {K} key
- */
-function lazyImport(key) {
-  /** @type {any | null} */
-  let packagePromise = null;
-
-  return function () {
-    if (!packagePromise) {
-      packagePromise = imports[key]();
-    }
-    return /** @type {ReturnType<typeof imports[K]>} */ (packagePromise);
-  };
-}
-
-export default /** @type {{ [K in keyof typeof imports]: () => ReturnType<typeof imports[K]> }} */ (
-  Object.fromEntries(
-    Object.keys(imports).map((key) => [
-      key,
-      lazyImport(/** @type {keyof typeof imports} */ (key)),
-    ]),
-  )
-);
--- a/websites/bitview/scripts/main.js
+++ b/websites/bitview/scripts/main.js
--- a/websites/bitview/scripts/options/series.js
+++ b/websites/bitview/scripts/options/series.js
@@ -178,7 +178,7 @@ export function fromBitcoin(colors, pattern, title, color) {
 /**
 * Create series from a SizePattern ({ sum, cumulative, average, min, max, percentiles })
 * @param {Colors} colors
- * @param {SizePattern} pattern
+ * @param {AnyStatsPattern} pattern
 * @param {string} title
 * @param {Color} [color]
 * @returns {AnyFetchedSeriesBlueprint[]}
@@ -241,7 +241,7 @@ export function fromBlockSize(colors, pattern, title, color) {
 /**
 * Create series from a SizePattern ({ average, sum, cumulative, min, max, percentiles })
 * @param {Colors} colors
- * @param {SizePattern} pattern
+ * @param {AnyStatsPattern} pattern
 * @param {string} title
 * @param {Unit} unit
 * @returns {AnyFetchedSeriesBlueprint[]}
--- a/websites/bitview/scripts/options/types.js
+++ b/websites/bitview/scripts/options/types.js
@@ -238,8 +238,8 @@
 * @property {HistogramSeriesFn} histogram
 * @property {(pattern: BlockCountPattern<any>, title: string, color?: Color) => AnyFetchedSeriesBlueprint[]} fromBlockCount
 * @property {(pattern: FullnessPattern<any>, title: string, color?: Color) => AnyFetchedSeriesBlueprint[]} fromBitcoin
- * @property {(pattern: SizePattern, title: string, color?: Color) => AnyFetchedSeriesBlueprint[]} fromBlockSize
- * @property {(pattern: SizePattern, title: string, unit: Unit) => AnyFetchedSeriesBlueprint[]} fromSizePattern
+ * @property {(pattern: AnyStatsPattern, title: string, color?: Color) => AnyFetchedSeriesBlueprint[]} fromBlockSize
+ * @property {(pattern: AnyStatsPattern, title: string, unit: Unit) => AnyFetchedSeriesBlueprint[]} fromSizePattern
 * @property {(pattern: FullnessPattern<any>, title: string, unit: Unit) => AnyFetchedSeriesBlueprint[]} fromFullnessPattern
 * @property {(pattern: FeeRatePattern<any>, title: string, unit: Unit) => AnyFetchedSeriesBlueprint[]} fromFeeRatePattern
 * @property {(pattern: CoinbasePattern, title: string) => AnyFetchedSeriesBlueprint[]} fromCoinbasePattern
--- a/websites/bitview/scripts/panes/chart/index.js
+++ b/websites/bitview/scripts/panes/chart/index.js
@@ -8,6 +8,9 @@ import { ios, canShare } from "../../utils/env.js";
 import { serdeChartableIndex, serdeOptNumber } from "../../utils/serde.js";
 import { throttle } from "../../utils/timing.js";
 import { Unit } from "../../utils/units.js";
+import signals from "../../signals.js";
+import { createChartElement } from "../../chart/index.js";
+import { webSockets } from "../../utils/ws.js";

 const keyPrefix = "chart";
 const ONE_BTC_IN_SATS = 100_000_000;
@@ -22,20 +25,12 @@ const CANDLE = "candle";
 /**
 * @param {Object} args
 * @param {Colors} args.colors
- * @param {CreateChartElement} args.createChartElement
 * @param {Accessor<ChartOption>} args.option
- * @param {Signals} args.signals
- * @param {WebSockets} args.webSockets
- * @param {Resources} args.resources
 * @param {BrkClient} args.brk
 */
 export function init({
  colors,
-  createChartElement,
  option,
-  signals,
-  webSockets,
-  resources,
  brk,
 }) {
  chartElement.append(createShadow("left"));
@@ -44,10 +39,7 @@ export function init({
  const { headerElement, headingElement } = createHeader();
  chartElement.append(headerElement);

-  const { index, fieldset } = createIndexSelector({
-    option,
-    signals,
-  });
+  const { index, fieldset } = createIndexSelector(option);

  const TIMERANGE_LS_KEY = signals.createMemo(
    () => `chart-timerange-${index()}`,
@@ -77,7 +69,6 @@ export function init({
    signals,
    colors,
    id: "charts",
-    resources,
    brk,
    index,
    timeScaleSetCallback: (unknownTimeScaleCallback) => {
@@ -525,11 +516,9 @@ export function init({
 }

 /**
- * @param {Object} args
- * @param {Accessor<ChartOption>} args.option
- * @param {Signals} args.signals
+ * @param {Accessor<ChartOption>} option
 */
-function createIndexSelector({ option, signals }) {
+function createIndexSelector(option) {
  const choices_ = /** @satisfies {ChartableIndexName[]} */ ([
    "timestamp",
    "date",
--- a/websites/bitview/scripts/panes/explorer.js
+++ b/websites/bitview/scripts/panes/explorer.js
@@ -1,25 +1,7 @@
 import { randomFromArray } from "../utils/array.js";
 import { explorerElement } from "../utils/elements.js";

-/**
- * @param {Object} args
- * @param {Colors} args.colors
- * @param {CreateChartElement} args.createChartElement
- * @param {Accessor<ChartOption>} args.option
- * @param {Signals} args.signals
- * @param {WebSockets} args.webSockets
- * @param {Resources} args.resources
- * @param {BrkClient} args.brk
- */
-export function init({
-  colors: _colors,
-  createChartElement: _createChartElement,
-  option: _option,
-  signals: _signals,
-  webSockets: _webSockets,
-  resources: _resources,
-  brk: _brk,
-}) {
+export function init() {
  const chain = window.document.createElement("div");
  chain.id = "chain";
  explorerElement.append(chain);
--- a/websites/bitview/scripts/panes/simulation.js
+++ b/websites/bitview/scripts/panes/simulation.js
@@ -18,15 +18,15 @@ import {
  numberToUSNumber,
 } from "../utils/format.js";
 import { serdeDate, serdeOptDate, serdeOptNumber } from "../utils/serde.js";
+import signals from "../signals.js";
+import { createChartElement } from "../chart/index.js";
+import { resources } from "../resources.js";

 /**
 * @param {Object} args
 * @param {Colors} args.colors
- * @param {CreateChartElement} args.createChartElement
- * @param {Signals} args.signals
- * @param {Resources} args.resources
 */
-export function init({ colors, createChartElement, signals, resources }) {
+export function init({ colors }) {
  /**
   * @typedef {Object} Frequency
   * @property {string} name
--- a/websites/bitview/scripts/panes/table.js
+++ b/websites/bitview/scripts/panes/table.js
@@ -6,14 +6,7 @@ import { tableElement } from "../utils/elements.js";
 import { serdeMetrics, serdeString } from "../utils/serde.js";
 import { resetParams } from "../utils/url.js";

-/**
- * @param {Object} args
- * @param {Signals} args.signals
- * @param {Option} args.option
- * @param {Resources} args.resources
- * @param {BrkClient} args.brk
- */
-export function init({ signals, option, resources, brk }) {
+export function init() {
  tableElement.innerHTML = "wip, will hopefuly be back soon, sorry !";

  // const parent = tableElement;
--- a/websites/bitview/scripts/resources.js
+++ b/websites/bitview/scripts/resources.js
@@ -25,105 +25,106 @@
 /** @typedef {MetricResource<unknown>} AnyMetricResource */

 /**
- * @typedef {ReturnType<typeof createResources>} Resources
+ * @typedef {{ createResource: typeof createResource, useMetricEndpoint: typeof useMetricEndpoint }} Resources
 */

+import signals from "./signals.js";
+
 /**
- * @param {Signals} signals
+ * Create a generic reactive resource wrapper for any async fetcher
+ * @template T
+ * @template {any[]} Args
+ * @param {(...args: Args) => Promise<T>} fetcher
+ * @returns {Resource<T>}
 */
-export function createResources(signals) {
+function createResource(fetcher) {
  const owner = signals.getOwner();
+  return signals.runWithOwner(owner, () => {
+    const data = signals.createSignal(/** @type {T | null} */ (null));
+    const loading = signals.createSignal(false);
+    const error = signals.createSignal(/** @type {Error | null} */ (null));

-  /**
-   * Create a generic reactive resource wrapper for any async fetcher
-   * @template T
-   * @template {any[]} Args
-   * @param {(...args: Args) => Promise<T>} fetcher
-   * @returns {Resource<T>}
-   */
-  function createResource(fetcher) {
-    return signals.runWithOwner(owner, () => {
-      const data = signals.createSignal(/** @type {T | null} */ (null));
-      const loading = signals.createSignal(false);
-      const error = signals.createSignal(/** @type {Error | null} */ (null));
-
-      return {
-        data,
-        loading,
-        error,
-        /**
-         * @param {Args} args
-         */
-        async fetch(...args) {
-          loading.set(true);
-          error.set(null);
-          try {
-            const result = await fetcher(...args);
-            data.set(() => result);
-            return result;
-          } catch (e) {
-            error.set(e instanceof Error ? e : new Error(String(e)));
-            return null;
-          } finally {
-            loading.set(false);
-          }
-        },
-      };
-    });
-  }
-
-  /**
-   * Create a reactive resource wrapper for a MetricEndpoint with multi-range support
-   * @template T
-   * @param {MetricEndpoint<T>} endpoint
-   * @returns {MetricResource<T>}
-   */
-  function useMetricEndpoint(endpoint) {
-    return signals.runWithOwner(owner, () => {
-      /** @type {Map<string, RangeState<T>>} */
-      const ranges = new Map();
-
+    return {
+      data,
+      loading,
+      error,
      /**
-       * Get or create range state
-       * @param {number} [from=-10000]
-       * @param {number} [to]
-       * @returns {RangeState<T>}
+       * @param {Args} args
       */
-      function range(from = -10000, to) {
-        const key = `${from}-${to ?? ""}`;
-        const existing = ranges.get(key);
-        if (existing) return existing;
-
-        /** @type {RangeState<T>} */
-        const state = {
-          response: signals.createSignal(/** @type {MetricData<T> | null} */ (null)),
-          loading: signals.createSignal(false),
-        };
-        ranges.set(key, state);
-        return state;
-      }
-
-      return {
-        path: endpoint.path,
-        range,
-        /**
-         * Fetch data for a range
-         * @param {number} [from=-10000]
-         * @param {number} [to]
-         */
-        async fetch(from = -10000, to) {
-          const r = range(from, to);
-          r.loading.set(true);
-          try {
-            const result = await endpoint.range(from, to, r.response.set);
-            return result;
-          } finally {
-            r.loading.set(false);
-          }
-        },
-      };
-    });
-  }
-
-  return { createResource, useMetricEndpoint };
+      async fetch(...args) {
+        loading.set(true);
+        error.set(null);
+        try {
+          const result = await fetcher(...args);
+          data.set(() => result);
+          return result;
+        } catch (e) {
+          error.set(e instanceof Error ? e : new Error(String(e)));
+          return null;
+        } finally {
+          loading.set(false);
+        }
+      },
+    };
+  });
 }
+
+/**
+ * Create a reactive resource wrapper for a MetricEndpoint with multi-range support
+ * @template T
+ * @param {MetricEndpoint<T>} endpoint
+ * @returns {MetricResource<T>}
+ */
+function useMetricEndpoint(endpoint) {
+  const owner = signals.getOwner();
+  return signals.runWithOwner(owner, () => {
+    /** @type {Map<string, RangeState<T>>} */
+    const ranges = new Map();
+
+    /**
+     * Get or create range state
+     * @param {number} [from=-10000]
+     * @param {number} [to]
+     * @returns {RangeState<T>}
+     */
+    function range(from = -10000, to) {
+      const key = `${from}-${to ?? ""}`;
+      const existing = ranges.get(key);
+      if (existing) return existing;
+
+      /** @type {RangeState<T>} */
+      const state = {
+        response: signals.createSignal(
+          /** @type {MetricData<T> | null} */ (null),
+        ),
+        loading: signals.createSignal(false),
+      };
+      ranges.set(key, state);
+      return state;
+    }
+
+    return {
+      path: endpoint.path,
+      range,
+      /**
+       * Fetch data for a range
+       * @param {number} [start=-10000]
+       * @param {number} [end]
+       */
+      async fetch(start = -10000, end) {
+        const r = range(start, end);
+        r.loading.set(true);
+        try {
+          const result = await endpoint
+            .slice(start, end)
+            .fetch(r.response.set);
+          return result;
+        } finally {
+          r.loading.set(false);
+        }
+      },
+    };
+  });
+}
+
+export const resources = { createResource, useMetricEndpoint };
--- a/websites/bitview/scripts/utils/ws.js
+++ b/websites/bitview/scripts/utils/ws.js
@@ -1,128 +1,114 @@
+import signals from "../signals.js";
+
 /**
- * @param {Signals} signals
+ * @template T
+ * @param {(callback: (value: T) => void) => WebSocket} creator
 */
-export function createWebSockets(signals) {
-  /**
-   * @template T
-   * @param {(callback: (value: T) => void) => WebSocket} creator
-   */
-  function createWebsocket(creator) {
-    let ws = /** @type {WebSocket | null} */ (null);
+function createWebsocket(creator) {
+  let ws = /** @type {WebSocket | null} */ (null);

-    const live = signals.createSignal(false);
-    const latest = signals.createSignal(/** @type {T | null} */ (null));
+  const live = signals.createSignal(false);
+  const latest = signals.createSignal(/** @type {T | null} */ (null));

-    function reinitWebSocket() {
-      if (!ws || ws.readyState === ws.CLOSED) {
-        console.log("ws: reinit");
-        resource.open();
-      }
+  function reinitWebSocket() {
+    if (!ws || ws.readyState === ws.CLOSED) {
+      console.log("ws: reinit");
+      resource.open();
    }
+  }

-    function reinitWebSocketIfDocumentNotHidden() {
-      !window.document.hidden && reinitWebSocket();
-    }
+  function reinitWebSocketIfDocumentNotHidden() {
+    !window.document.hidden && reinitWebSocket();
+  }

-    const resource = {
-      live,
-      latest,
-      open() {
-        ws = creator((value) => latest.set(() => value));
+  const resource = {
+    live,
+    latest,
+    open() {
+      ws = creator((value) => latest.set(() => value));

-        ws.addEventListener("open", () => {
-          console.log("ws: open");
-          live.set(true);
-        });
+      ws.addEventListener("open", () => {
+        console.log("ws: open");
+        live.set(true);
+      });

-        ws.addEventListener("close", () => {
-          console.log("ws: close");
-          live.set(false);
-        });
-
-        window.document.addEventListener(
-          "visibilitychange",
-          reinitWebSocketIfDocumentNotHidden,
-        );
-
-        window.document.addEventListener("online", reinitWebSocket);
-      },
-      close() {
-        ws?.close();
-        window.document.removeEventListener(
-          "visibilitychange",
-          reinitWebSocketIfDocumentNotHidden,
-        );
-        window.document.removeEventListener("online", reinitWebSocket);
+      ws.addEventListener("close", () => {
+        console.log("ws: close");
        live.set(false);
-        ws = null;
-      },
-    };
+      });

-    return resource;
-  }
-
-  /**
-   * @param {(candle: CandlestickData) => void} callback
-   */
-  function krakenCandleWebSocketCreator(callback) {
-    const ws = new WebSocket("wss://ws.kraken.com/v2");
-
-    ws.addEventListener("open", () => {
-      ws.send(
-        JSON.stringify({
-          method: "subscribe",
-          params: {
-            channel: "ohlc",
-            symbol: ["BTC/USD"],
-            interval: 1440,
-          },
-        }),
+      window.document.addEventListener(
+        "visibilitychange",
+        reinitWebSocketIfDocumentNotHidden,
      );
-    });

-    ws.addEventListener("message", (message) => {
-      const result = JSON.parse(message.data);
+      window.document.addEventListener("online", reinitWebSocket);
+    },
+    close() {
+      ws?.close();
+      window.document.removeEventListener(
+        "visibilitychange",
+        reinitWebSocketIfDocumentNotHidden,
+      );
+      window.document.removeEventListener("online", reinitWebSocket);
+      live.set(false);
+      ws = null;
+    },
+  };

-      if (result.channel !== "ohlc") return;
+  return resource;
+}

-      const { interval_begin, open, high, low, close } = result.data.at(-1);
+/**
+ * @param {(candle: CandlestickData) => void} callback
+ */
+function krakenCandleWebSocketCreator(callback) {
+  const ws = new WebSocket("wss://ws.kraken.com/v2");

-      /** @type {CandlestickData} */
-      const candle = {
-        // index: -1,
-        time: new Date(interval_begin).valueOf() / 1000,
-        open: Number(open),
-        high: Number(high),
-        low: Number(low),
-        close: Number(close),
-      };
-
-      candle && callback({ ...candle });
-    });
-
-    return ws;
-  }
-
-  /** @type {ReturnType<typeof createWebsocket<CandlestickData>>} */
-  const kraken1dCandle = createWebsocket((callback) =>
-    krakenCandleWebSocketCreator(callback),
-  );
-
-  kraken1dCandle.open();
-
-  signals.createEffect(kraken1dCandle.latest, (latest) => {
-    if (latest) {
-      const close = latest.close;
-      console.log("close:", close);
-
-      window.document.title = `${latest.close.toLocaleString("en-us")} | ${
-        window.location.host
-      }`;
-    }
+  ws.addEventListener("open", () => {
+    ws.send(
+      JSON.stringify({
+        method: "subscribe",
+        params: {
+          channel: "ohlc",
+          symbol: ["BTC/USD"],
+          interval: 1440,
+        },
+      }),
+    );
  });

-  return {
-    kraken1dCandle,
-  };
+  ws.addEventListener("message", (message) => {
+    const result = JSON.parse(message.data);
+
+    if (result.channel !== "ohlc") return;
+
+    const { interval_begin, open, high, low, close } = result.data.at(-1);
+
+    /** @type {CandlestickData} */
+    const candle = {
+      // index: -1,
+      time: new Date(interval_begin).valueOf() / 1000,
+      open: Number(open),
+      high: Number(high),
+      low: Number(low),
+      close: Number(close),
+    };
+
+    candle && callback({ ...candle });
+  });
+
+  return ws;
 }
-/** @typedef {ReturnType<typeof createWebSockets>} WebSockets */
+
+/** @type {ReturnType<typeof createWebsocket<CandlestickData>>} */
+const kraken1dCandle = createWebsocket((callback) =>
+  krakenCandleWebSocketCreator(callback),
+);
+
+kraken1dCandle.open();
+
+export const webSockets = {
+  kraken1dCandle,
+};
+/** @typedef {typeof webSockets} WebSockets */