⚡ Bolt: [performance improvement] Pre-compute basenames and use single-pass Sets for diffTests

.jules/bolt.md

@@ -8,3 +8,7 @@
 ## 2024-05-24 - Pre-compile RegExp in nested loops
 **Learning:** Instantiating `new RegExp()` inside nested array methods like `.filter` and `.some` creates a severe O(N*M) performance bottleneck, especially when matching two large lists (e.g., documented tests vs. actual test files).
 **Action:** Always pre-compile regular expressions and derived strings into an array of "matcher" objects outside of the loop before iterating, which shifts the instantiation cost from O(N*M) to O(N).
+
+## 2024-05-30 - [Optimize N*M Array Comparisons]
+**Learning:** In string-heavy O(N*M) nested array comparisons (like `.filter().some()` to compare test files), calling string processing functions like `basename()` repeatedly for the same item during every pass is a major bottleneck.
+**Action:** Avoid redundant string processing overhead by pre-computing string formats (like basenames) into objects outside the loop, and use `Set`s for single-pass cross-comparisons instead of multiple O(N*M) array iterations.

cli/commands/diff.mjs

@@ -363,17 +363,29 @@ function diffTests(dir, config = {}) {
     };
   });
 
-  const matches = (matcher, codeRel) => {
-    const subject = matcher.hasSlash ? codeRel : basename(codeRel);
-    return matcher.rx.test(subject);
-  };
+  // PERFORMANCE OPTIMIZATION: Avoid redundant string processing overhead by
+  // pre-computing basenames outside the loop, and replace multiple nested
+  // .filter().some() passes with a single-pass cross-comparison using Sets.
+  const codeObjects = codeArr.map(c => ({ rel: c, base: basename(c) }));
+  const matchedDocs = new Set();
+  const matchedCode = new Set();
+
+  for (const doc of docMatchers) {
+    for (const code of codeObjects) {
+      const subject = doc.hasSlash ? code.rel : code.base;
+      if (doc.rx.test(subject)) {
+        matchedDocs.add(doc.original);
+        matchedCode.add(code.rel);
+      }
+    }
+  }
 
   return {
     title: 'Test Files',
     icon: '🧪',
-    onlyInDocs: docMatchers.filter(m => !codeArr.some(c => matches(m, c))).map(m => m.original),
-    onlyInCode: codeArr.filter(c => !docMatchers.some(m => matches(m, c))),
-    matched: docMatchers.filter(m => codeArr.some(c => matches(m, c))).map(m => m.original),
+    onlyInDocs: docMatchers.filter(m => !matchedDocs.has(m.original)).map(m => m.original),
+    onlyInCode: codeObjects.filter(c => !matchedCode.has(c.rel)).map(c => c.rel),
+    matched: docMatchers.filter(m => matchedDocs.has(m.original)).map(m => m.original),
   };
 }
 

cli/validators/docs-diff.mjs

@@ -188,15 +188,27 @@ function diffTests(dir, config) {
     };
   });
 
-  const matches = (matcher, codeRel) => {
-    const subject = matcher.hasSlash ? codeRel : basename(codeRel);
-    return matcher.rx.test(subject);
-  };
+  // PERFORMANCE OPTIMIZATION: Avoid redundant string processing overhead by
+  // pre-computing basenames outside the loop, and replace multiple nested
+  // .filter().some() passes with a single-pass cross-comparison using Sets.
+  const codeObjects = codeArr.map(c => ({ rel: c, base: basename(c) }));
+  const matchedDocs = new Set();
+  const matchedCode = new Set();
+
+  for (const doc of docMatchers) {
+    for (const code of codeObjects) {
+      const subject = doc.hasSlash ? code.rel : code.base;
+      if (doc.rx.test(subject)) {
+        matchedDocs.add(doc.original);
+        matchedCode.add(code.rel);
+      }
+    }
+  }
 
   return {
     title: 'Test Files',
-    onlyInDocs: docMatchers.filter(m => !codeArr.some(c => matches(m, c))).map(m => m.original),
-    onlyInCode: codeArr.filter(c => !docMatchers.some(m => matches(m, c))),
+    onlyInDocs: docMatchers.filter(m => !matchedDocs.has(m.original)).map(m => m.original),
+    onlyInCode: codeObjects.filter(c => !matchedCode.has(c.rel)).map(c => c.rel),
   };
 }