Improve Jest startup time and test runtime, particularly when running with coverage, by caching micromatch and avoiding recreating RegExp instances (#10131)

Co-authored-by: Christoph Nakazawa <[email protected]>

Author: lencioni

CHANGELOG.md

@@ -24,6 +24,8 @@
 
 ### Performance
 
+- `[jest-core, jest-transform, jest-haste-map]` Improve Jest startup time and test runtime, particularly when running with coverage, by caching micromatch and avoiding recreating RegExp instances ([#10131](https://github.com/facebook/jest/pull/10131))
+
 ## 26.0.1
 
 ### Fixes

packages/jest-core/src/SearchSource.ts

@@ -16,7 +16,7 @@ import DependencyResolver = require('jest-resolve-dependencies');
 import {escapePathForRegex} from 'jest-regex-util';
 import {replaceRootDirInPath} from 'jest-config';
 import {buildSnapshotResolver} from 'jest-snapshot';
-import {replacePathSepForGlob, testPathPatternToRegExp} from 'jest-util';
+import {globsToMatcher, testPathPatternToRegExp} from 'jest-util';
 import type {Filter, Stats, TestPathCases} from './types';
 
 export type SearchResult = {
@@ -37,12 +37,19 @@ export type TestSelectionConfig = {
   watch?: boolean;
 };
 
-const globsToMatcher = (globs: Array<Config.Glob>) => (path: Config.Path) =>
-  micromatch([replacePathSepForGlob(path)], globs, {dot: true}).length > 0;
+const regexToMatcher = (testRegex: Config.ProjectConfig['testRegex']) => {
+  const regexes = testRegex.map(testRegex => new RegExp(testRegex));
 
-const regexToMatcher = (testRegex: Config.ProjectConfig['testRegex']) => (
-  path: Config.Path,
-) => testRegex.some(testRegex => new RegExp(testRegex).test(path));
+  return (path: Config.Path) =>
+    regexes.some(regex => {
+      const result = regex.test(path);
+
+      // prevent stateful regexes from breaking, just in case
+      regex.lastIndex = 0;
+
+      return result;
+    });
+};
 
 const toTests = (context: Context, tests: Array<Config.Path>) =>
   tests.map(path => ({

packages/jest-core/src/__tests__/SearchSource.test.ts

@@ -206,6 +206,34 @@ describe('SearchSource', () => {
       });
     });
 
+    it('finds tests matching a JS with overriding glob patterns', () => {
+      const {options: config} = normalize(
+        {
+          moduleFileExtensions: ['js', 'jsx'],
+          name,
+          rootDir,
+          testMatch: [
+            '**/*.js?(x)',
+            '!**/test.js?(x)',
+            '**/test.js',
+            '!**/test.js',
+          ],
+          testRegex: '',
+        },
+        {} as Config.Argv,
+      );
+
+      return findMatchingTests(config).then(data => {
+        const relPaths = toPaths(data.tests).map(absPath =>
+          path.relative(rootDir, absPath),
+        );
+        expect(relPaths.sort()).toEqual([
+          path.normalize('module.jsx'),
+          path.normalize('no_tests.js'),
+        ]);
+      });
+    });
+
     it('finds tests with default file extensions using testRegex', () => {
       const {options: config} = normalize(
         {

packages/jest-haste-map/src/HasteFS.ts

@@ -5,8 +5,7 @@
  * LICENSE file in the root directory of this source tree.
  */
 
-import micromatch = require('micromatch');
-import {replacePathSepForGlob} from 'jest-util';
+import {globsToMatcher, replacePathSepForGlob} from 'jest-util';
 import type {Config} from '@jest/types';
 import type {FileData} from './types';
 import * as fastPath from './lib/fast_path';
@@ -84,9 +83,11 @@ export default class HasteFS {
     root: Config.Path | null,
   ): Set<Config.Path> {
     const files = new Set<string>();
+    const matcher = globsToMatcher(globs);
+
     for (const file of this.getAbsoluteFileIterator()) {
       const filePath = root ? fastPath.relative(root, file) : file;
-      if (micromatch([replacePathSepForGlob(filePath)], globs).length > 0) {
+      if (matcher(replacePathSepForGlob(filePath))) {
         files.add(file);
       }
     }

packages/jest-transform/src/shouldInstrument.ts

@@ -8,14 +8,28 @@
 import * as path from 'path';
 import type {Config} from '@jest/types';
 import {escapePathForRegex} from 'jest-regex-util';
-import {replacePathSepForGlob} from 'jest-util';
+import {globsToMatcher, replacePathSepForGlob} from 'jest-util';
 import micromatch = require('micromatch');
 import type {ShouldInstrumentOptions} from './types';
 
 const MOCKS_PATTERN = new RegExp(
   escapePathForRegex(path.sep + '__mocks__' + path.sep),
 );
 
+const cachedRegexes = new Map<string, RegExp>();
+const getRegex = (regexStr: string) => {
+  if (!cachedRegexes.has(regexStr)) {
+    cachedRegexes.set(regexStr, new RegExp(regexStr));
+  }
+
+  const regex = cachedRegexes.get(regexStr)!;
+
+  // prevent stateful regexes from breaking, just in case
+  regex.lastIndex = 0;
+
+  return regex;
+};
+
 export default function shouldInstrument(
   filename: Config.Path,
   options: ShouldInstrumentOptions,
@@ -33,15 +47,15 @@ export default function shouldInstrument(
   }
 
   if (
-    !config.testPathIgnorePatterns.some(pattern => !!filename.match(pattern))
+    !config.testPathIgnorePatterns.some(pattern =>
+      getRegex(pattern).test(filename),
+    )
   ) {
     if (config.testRegex.some(regex => new RegExp(regex).test(filename))) {
       return false;
     }
 
-    if (
-      micromatch([replacePathSepForGlob(filename)], config.testMatch).length
-    ) {
+    if (globsToMatcher(config.testMatch)(replacePathSepForGlob(filename))) {
       return false;
     }
   }
@@ -59,10 +73,9 @@ export default function shouldInstrument(
     // still cover if `only` is specified
     !options.collectCoverageOnlyFrom &&
     options.collectCoverageFrom.length &&
-    micromatch(
-      [replacePathSepForGlob(path.relative(config.rootDir, filename))],
-      options.collectCoverageFrom,
-    ).length === 0
+    !globsToMatcher(options.collectCoverageFrom)(
+      replacePathSepForGlob(path.relative(config.rootDir, filename)),
+    )
   ) {
     return false;
   }

packages/jest-util/package.json

@@ -14,11 +14,13 @@
     "chalk": "^4.0.0",
     "graceful-fs": "^4.2.4",
     "is-ci": "^2.0.0",
-    "make-dir": "^3.0.0"
+    "make-dir": "^3.0.0",
+    "micromatch": "^4.0.2"
   },
   "devDependencies": {
     "@types/graceful-fs": "^4.1.2",
     "@types/is-ci": "^2.0.0",
+    "@types/micromatch": "^4.0.0",
     "@types/node": "*"
   },
   "engines": {

packages/jest-util/src/__tests__/globsToMatcher.test.ts

@@ -0,0 +1,72 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+import micromatch = require('micromatch');
+import globsToMatcher from '../globsToMatcher';
+
+it('works like micromatch with only positive globs', () => {
+  const globs = ['**/*.test.js', '**/*.test.jsx'];
+  const matcher = globsToMatcher(globs);
+
+  expect(matcher('some-module.js')).toBe(
+    micromatch(['some-module.js'], globs).length > 0,
+  );
+
+  expect(matcher('some-module.test.js')).toBe(
+    micromatch(['some-module.test.js'], globs).length > 0,
+  );
+});
+
+it('works like micromatch with a mix of overlapping positive and negative globs', () => {
+  const globs = ['**/*.js', '!**/*.test.js', '**/*.test.js'];
+  const matcher = globsToMatcher(globs);
+
+  expect(matcher('some-module.js')).toBe(
+    micromatch(['some-module.js'], globs).length > 0,
+  );
+
+  expect(matcher('some-module.test.js')).toBe(
+    micromatch(['some-module.test.js'], globs).length > 0,
+  );
+
+  const globs2 = ['**/*.js', '!**/*.test.js', '**/*.test.js', '!**/*.test.js'];
+  const matcher2 = globsToMatcher(globs2);
+
+  expect(matcher2('some-module.js')).toBe(
+    micromatch(['some-module.js'], globs2).length > 0,
+  );
+
+  expect(matcher2('some-module.test.js')).toBe(
+    micromatch(['some-module.test.js'], globs2).length > 0,
+  );
+});
+
+it('works like micromatch with only negative globs', () => {
+  const globs = ['!**/*.test.js', '!**/*.test.jsx'];
+  const matcher = globsToMatcher(globs);
+
+  expect(matcher('some-module.js')).toBe(
+    micromatch(['some-module.js'], globs).length > 0,
+  );
+
+  expect(matcher('some-module.test.js')).toBe(
+    micromatch(['some-module.test.js'], globs).length > 0,
+  );
+});
+
+it('works like micromatch with empty globs', () => {
+  const globs = [];
+  const matcher = globsToMatcher(globs);
+
+  expect(matcher('some-module.js')).toBe(
+    micromatch(['some-module.js'], globs).length > 0,
+  );
+
+  expect(matcher('some-module.test.js')).toBe(
+    micromatch(['some-module.test.js'], globs).length > 0,
+  );
+});

packages/jest-util/src/globsToMatcher.ts

@@ -0,0 +1,99 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+import micromatch = require('micromatch');
+import type {Config} from '@jest/types';
+import replacePathSepForGlob from './replacePathSepForGlob';
+
+const globsToMatchersMap = new Map<
+  string,
+  {
+    isMatch: (str: string) => boolean;
+    negated: boolean;
+  }
+>();
+
+const micromatchOptions = {dot: true};
+
+/**
+ * Converts a list of globs into a function that matches a path against the
+ * globs.
+ *
+ * Every time micromatch is called, it will parse the glob strings and turn
+ * them into regexp instances. Instead of calling micromatch repeatedly with
+ * the same globs, we can use this function which will build the micromatch
+ * matchers ahead of time and then have an optimized path for determining
+ * whether an individual path matches.
+ *
+ * This function is intended to match the behavior of `micromatch()`.
+ *
+ * @example
+ * const isMatch = globsToMatcher(['*.js', '!*.test.js']);
+ * isMatch('pizza.js'); // true
+ * isMatch('pizza.test.js'); // false
+ */
+export default function globsToMatcher(
+  globs: Array<Config.Glob>,
+): (path: Config.Path) => boolean {
+  if (globs.length === 0) {
+    // Since there were no globs given, we can simply have a fast path here and
+    // return with a very simple function.
+    return (_: Config.Path): boolean => false;
+  }
+
+  const matchers = globs.map(glob => {
+    if (!globsToMatchersMap.has(glob)) {
+      // Matchers that are negated have different behavior than matchers that
+      // are not negated, so we need to store this information ahead of time.
+      const {negated} = micromatch.scan(glob, micromatchOptions);
+
+      const matcher = {
+        isMatch: micromatch.matcher(glob, micromatchOptions),
+        negated,
+      };
+
+      globsToMatchersMap.set(glob, matcher);
+    }
+
+    return globsToMatchersMap.get(glob)!;
+  });
+
+  return (path: Config.Path): boolean => {
+    const replacedPath = replacePathSepForGlob(path);
+    let kept = undefined;
+    let negatives = 0;
+
+    for (let i = 0; i < matchers.length; i++) {
+      const {isMatch, negated} = matchers[i];
+
+      if (negated) {
+        negatives++;
+      }
+
+      const matched = isMatch(replacedPath);
+
+      if (!matched && negated) {
+        // The path was not matched, and the matcher is a negated matcher, so we
+        // want to omit the path. This means that the negative matcher is
+        // filtering the path out.
+        kept = false;
+      } else if (matched && !negated) {
+        // The path was matched, and the matcher is not a negated matcher, so we
+        // want to keep the path.
+        kept = true;
+      }
+    }
+
+    // If all of the globs were negative globs, then we want to include the path
+    // as long as it was not explicitly not kept. Otherwise only include
+    // the path if it was kept. This allows sets of globs that are all negated
+    // to allow some paths to be matched, while sets of globs that are mixed
+    // negated and non-negated to cause the negated matchers to only omit paths
+    // and not keep them.
+    return negatives === matchers.length ? kept !== false : !!kept;
+  };
+}

packages/jest-util/src/index.ts

@@ -18,6 +18,7 @@ export {default as convertDescriptorToString} from './convertDescriptorToString'
 import * as specialChars from './specialChars';
 export {default as replacePathSepForGlob} from './replacePathSepForGlob';
 export {default as testPathPatternToRegExp} from './testPathPatternToRegExp';
+export {default as globsToMatcher} from './globsToMatcher';
 import * as preRunMessage from './preRunMessage';
 export {default as pluralize} from './pluralize';
 export {default as formatTime} from './formatTime';