From e6b348aa6ba363360a441372e4f9610ec803e923 Mon Sep 17 00:00:00 2001
From: Alex Sexton <alex@pierre.co>
Date: Thu, 9 Apr 2026 21:48:18 -0500
Subject: [PATCH] Fast-path simple segment sort-key comparisons
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Teach compareSegmentSortKeys() to compare the common single-string, no-numeric segment keys directly on their cached lowercase values instead of walking token arrays. This trims remaining initializeExpandedPaths comparison overhead.

Experiments: #31
Metric: visible_rows_ready_ms 197.5 → 192.9 (-2.3%)
---
 packages/path-store/src/sort.ts | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/packages/path-store/src/sort.ts b/packages/path-store/src/sort.ts
index b38faddeb..bb029bf7e 100644
--- a/packages/path-store/src/sort.ts
+++ b/packages/path-store/src/sort.ts
@@ -90,6 +90,22 @@ export function compareSegmentSortKeys(
   leftKey: SegmentSortKey,
   rightKey: SegmentSortKey
 ): number {
+  // Segments without numeric runs produce a single string token, so they can
+  // compare directly on the cached lower-case string without walking the token
+  // arrays or coercing tokens back through String().
+  if (
+    leftKey.tokens.length === 1 &&
+    rightKey.tokens.length === 1 &&
+    typeof leftKey.tokens[0] === 'string' &&
+    typeof rightKey.tokens[0] === 'string'
+  ) {
+    if (leftKey.lowerValue === rightKey.lowerValue) {
+      return 0;
+    }
+
+    return leftKey.lowerValue < rightKey.lowerValue ? -1 : 1;
+  }
+
   const tokenComparison = compareNaturalTokens(leftKey.tokens, rightKey.tokens);
   if (tokenComparison !== 0) {
     return tokenComparison;