perf(core): cache TraceMap and parsed sourcemaps, use Set for coverage file lookup (#1074)

Author: fi3ework

packages/core/src/coverage/generate.ts

@@ -74,7 +74,7 @@ export async function generateCoverage(
     }
 
     if (coverage.include?.length) {
-      const coveredFiles = finalCoverageMap.files().map(normalize);
+      const coveredFilesSet = new Set(finalCoverageMap.files().map(normalize));
 
       let isTimeout = false;
 
@@ -89,7 +89,7 @@ export async function generateCoverage(
             const includedFiles = await getIncludedFiles(coverage, p.rootPath);
 
             const uncoveredFiles = includedFiles.filter(
-              (file) => !coveredFiles.includes(normalize(file)),
+              (file) => !coveredFilesSet.has(normalize(file)),
             );
 
             if (uncoveredFiles.length) {
@@ -113,7 +113,8 @@ export async function generateCoverage(
       }
 
       // should be better to filter files before swc coverage is processed
-      finalCoverageMap.filter((file) => allFiles.includes(normalize(file)));
+      const allFilesSet = new Set(allFiles.map(normalize));
+      finalCoverageMap.filter((file) => allFilesSet.has(normalize(file)));
     }
 
     // Generate coverage reports

packages/core/src/reporter/md.ts

@@ -749,6 +749,10 @@ const parseErrorStacktrace = async ({
   getSourcemap?: GetSourcemap;
   fullStack?: boolean;
 }): Promise<StackFrame[]> => {
+  // Cache TraceMap per file to avoid redundant VLQ decoding when multiple
+  // stack frames originate from the same source file.
+  const traceMapCache = new Map<string, TraceMap>();
+
   const frames = parseStackTrace(stack)
     .filter((frame) => {
       if (fullStack) return true;
@@ -778,7 +782,11 @@ const parseErrorStacktrace = async ({
         };
       }
 
-      const traceMap = new TraceMap(sourcemap);
+      let traceMap = traceMapCache.get(file);
+      if (!traceMap) {
+        traceMap = new TraceMap(sourcemap);
+        traceMapCache.set(file, traceMap);
+      }
       const { line, column, source, name } = originalPositionFor(traceMap, {
         line: frame.lineNumber || 1,
         column: frame.column || 1,
@@ -1195,13 +1203,14 @@ export class MdReporter implements Reporter {
                 })
               : [];
 
-            const fullFrames = error.stack
-              ? await parseErrorStacktrace({
-                  stack: error.stack,
-                  getSourcemap,
-                  fullStack: error.fullStack,
-                })
-              : candidateFrames;
+            const fullFrames =
+              error.fullStack && error.stack
+                ? await parseErrorStacktrace({
+                    stack: error.stack,
+                    getSourcemap,
+                    fullStack: true,
+                  })
+                : candidateFrames;
 
             const trimmedFrames = resolveStackFrames(fullFrames, this.options);
             const topFrame = fullFrames[0] ?? candidateFrames[0];

packages/core/src/utils/error.ts

@@ -166,6 +166,10 @@ export async function parseErrorStacktrace({
   stack: string;
   getSourcemap?: GetSourcemap;
 }): Promise<StackFrame[]> {
+  // Cache TraceMap per file to avoid redundant VLQ decoding when multiple
+  // stack frames originate from the same source file.
+  const traceMapCache = new Map<string, TraceMap>();
+
   const stackFrames = await Promise.all(
     stackTraceParse(stack)
       .filter((frame) =>
@@ -177,7 +181,11 @@ export async function parseErrorStacktrace({
       .map(async (frame) => {
         const sourcemap = await getSourcemap?.(frame.file!);
         if (sourcemap) {
-          const traceMap = new TraceMap(sourcemap);
+          let traceMap = traceMapCache.get(frame.file!);
+          if (!traceMap) {
+            traceMap = new TraceMap(sourcemap);
+            traceMapCache.set(frame.file!, traceMap);
+          }
           const { line, column, source, name } = originalPositionFor(traceMap, {
             line: frame.lineNumber!,
             column: frame.column!,