feat: Create a quality gate for typescript coverage (#27717)

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## **Description**

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also include relevant motivation and context. Have in mind the following
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1. What is the reason for the change?
2. What is the improvement/solution?
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[![Open in GitHub
Codespaces](https://github.com/codespaces/badge.svg)](https://codespaces.new/MetaMask/metamask-extension/pull/27717?quickstart=1)

This PR introduces a quality gate for typescript coverage. It updates
the existing fitness function to disallow the creation of new js and jsx
files in the repository.

## **Related issues**

Fixes: MetaMask/MetaMask-planning#2399

## **Manual testing steps**

1. After committing a javascript file, the fitness function should fail.

## **Screenshots/Recordings**

Not applicable

## **Pre-merge author checklist**

- [x] I've followed [MetaMask Contributor
Docs](https://github.com/MetaMask/contributor-docs) and [MetaMask
Extension Coding
Standards](https://github.com/MetaMask/metamask-extension/blob/develop/.github/guidelines/CODING_GUIDELINES.md).
- [x] I've completed the PR template to the best of my ability
- [x] I’ve included tests if applicable
- [x] I’ve documented my code using [JSDoc](https://jsdoc.app/) format
if applicable
- [x] I’ve applied the right labels on the PR (see [labeling
guidelines](https://github.com/MetaMask/metamask-extension/blob/develop/.github/guidelines/LABELING_GUIDELINES.md)).
Not required for external contributors.

## **Pre-merge reviewer checklist**

- [ ] I've manually tested the PR (e.g. pull and build branch, run the
app, test code being changed).
- [ ] I confirm that this PR addresses all acceptance criteria described
in the ticket it closes and includes the necessary testing evidence such
as recordings and or screenshots.

.github/workflows/fitness-functions.yml

@@ -2,12 +2,14 @@ name: Fitness Functions CI
 
 on:
   pull_request:
-    types: [assigned, opened, synchronize, reopened]
+    types:
+      - opened
+      - reopened
+      - synchronize
 
 jobs:
   build:
     runs-on: ubuntu-latest
-
     steps:
       - name: Checkout code
         uses: actions/checkout@v4

development/fitness-functions/common/constants.test.ts

@@ -1,8 +1,34 @@
-import { EXCLUDE_E2E_TESTS_REGEX, SHARED_FOLDER_JS_REGEX } from './constants';
+import { E2E_TESTS_REGEX, JS_REGEX } from './constants';
 
 describe('Regular Expressions used in Fitness Functions', (): void => {
-  describe(`EXCLUDE_E2E_TESTS_REGEX "${EXCLUDE_E2E_TESTS_REGEX}"`, (): void => {
+  describe(`E2E_TESTS_REGEX "${E2E_TESTS_REGEX}"`, (): void => {
     const PATHS_IT_SHOULD_MATCH = [
+      // JS, TS, JSX, and TSX files inside the
+      // test/e2e directory
+      'test/e2e/file.js',
+      'test/e2e/path/file.ts',
+      'test/e2e/much/longer/path/file.jsx',
+      'test/e2e/much/longer/path/file.tsx',
+      // development/fitness-functions directory
+      'development/fitness-functions/file.js',
+      'development/fitness-functions/path/file.ts',
+      'development/fitness-functions/much/longer/path/file.jsx',
+      'development/fitness-functions/much/longer/path/file.tsx',
+      // development/webpack directory
+      'development/webpack/file.js',
+      'development/webpack/path/file.ts',
+      'development/webpack/much/longer/path/file.jsx',
+      'development/webpack/much/longer/path/file.tsx',
+    ];
+
+    const PATHS_IT_SHOULD_NOT_MATCH = [
+      // any files without JS, TS, JSX or TSX extension
+      'file',
+      'file.extension',
+      'path/file.extension',
+      'much/longer/path/file.extension',
+      // JS, TS, JSX, and TSX files outside
+      // the test/e2e, development/fitness-functions, development/webpack directories
       'file.js',
       'path/file.js',
       'much/longer/path/file.js',
@@ -12,39 +38,15 @@ describe('Regular Expressions used in Fitness Functions', (): void => {
       'file.jsx',
       'path/file.jsx',
       'much/longer/path/file.jsx',
-    ];
-
-    const PATHS_IT_SHOULD_NOT_MATCH = [
-      // any without JS, TS, JSX or TSX extension
-      'file',
-      'file.extension',
-      'path/file.extension',
-      'much/longer/path/file.extension',
-      // any in the test/e2e directory
-      'test/e2e/file',
-      'test/e2e/file.extension',
-      'test/e2e/path/file.extension',
-      'test/e2e/much/longer/path/file.extension',
-      'test/e2e/file.js',
-      'test/e2e/path/file.ts',
-      'test/e2e/much/longer/path/file.jsx',
-      'test/e2e/much/longer/path/file.tsx',
-      // any in the development/fitness-functions directory
-      'development/fitness-functions/file',
-      'development/fitness-functions/file.extension',
-      'development/fitness-functions/path/file.extension',
-      'development/fitness-functions/much/longer/path/file.extension',
-      'development/fitness-functions/file.js',
-      'development/fitness-functions/path/file.ts',
-      'development/fitness-functions/much/longer/path/file.jsx',
-      'development/fitness-functions/much/longer/path/file.tsx',
+      'file.tsx',
+      'path/file.tsx',
+      'much/longer/path/file.tsx',
     ];
 
     describe('included paths', (): void => {
       PATHS_IT_SHOULD_MATCH.forEach((path: string): void => {
         it(`should match "${path}"`, (): void => {
-          const result = new RegExp(EXCLUDE_E2E_TESTS_REGEX, 'u').test(path);
-
+          const result = E2E_TESTS_REGEX.test(path);
           expect(result).toStrictEqual(true);
         });
       });
@@ -53,22 +55,23 @@ describe('Regular Expressions used in Fitness Functions', (): void => {
     describe('excluded paths', (): void => {
       PATHS_IT_SHOULD_NOT_MATCH.forEach((path: string): void => {
         it(`should not match "${path}"`, (): void => {
-          const result = new RegExp(EXCLUDE_E2E_TESTS_REGEX, 'u').test(path);
-
+          const result = E2E_TESTS_REGEX.test(path);
           expect(result).toStrictEqual(false);
         });
       });
     });
   });
 
-  describe(`SHARED_FOLDER_JS_REGEX "${SHARED_FOLDER_JS_REGEX}"`, (): void => {
+  describe(`JS_REGEX "${JS_REGEX}"`, (): void => {
     const PATHS_IT_SHOULD_MATCH = [
+      'app/much/longer/path/file.js',
+      'app/much/longer/path/file.jsx',
+      'offscreen/path/file.js',
+      'offscreen/path/file.jsx',
       'shared/file.js',
-      'shared/path/file.js',
-      'shared/much/longer/path/file.js',
       'shared/file.jsx',
-      'shared/path/file.jsx',
-      'shared/much/longer/path/file.jsx',
+      'ui/much/longer/path/file.js',
+      'ui/much/longer/path/file.jsx',
     ];
 
     const PATHS_IT_SHOULD_NOT_MATCH = [
@@ -80,13 +83,15 @@ describe('Regular Expressions used in Fitness Functions', (): void => {
       'file.ts',
       'path/file.ts',
       'much/longer/path/file.tsx',
+      // any JS or JSX files outside the app, offscreen, shared, and ui directories
+      'test/longer/path/file.js',
+      'random/longer/path/file.jsx',
     ];
 
     describe('included paths', (): void => {
       PATHS_IT_SHOULD_MATCH.forEach((path: string): void => {
         it(`should match "${path}"`, (): void => {
-          const result = new RegExp(SHARED_FOLDER_JS_REGEX, 'u').test(path);
-
+          const result = JS_REGEX.test(path);
           expect(result).toStrictEqual(true);
         });
       });
@@ -95,8 +100,7 @@ describe('Regular Expressions used in Fitness Functions', (): void => {
     describe('excluded paths', (): void => {
       PATHS_IT_SHOULD_NOT_MATCH.forEach((path: string): void => {
         it(`should not match "${path}"`, (): void => {
-          const result = new RegExp(SHARED_FOLDER_JS_REGEX, 'u').test(path);
-
+          const result = JS_REGEX.test(path);
           expect(result).toStrictEqual(false);
         });
       });

development/fitness-functions/common/constants.ts

@@ -1,15 +1,17 @@
-// include JS, TS, JSX, TSX files only excluding files in the e2e tests and
-// fitness functions directories
-const EXCLUDE_E2E_TESTS_REGEX =
-  '^(?!test/e2e)(?!development/fitness|development/webpack).*.(js|ts|jsx|tsx)$';
+// include JS, TS, JSX, TSX files only in the
+// test/e2e
+// development/fitness-functions
+// development/webpack directories
+const E2E_TESTS_REGEX =
+  /^(test\/e2e|development\/fitness-functions|development\/webpack).*\.(js|ts|jsx|tsx)$/u;
 
-// include JS and JSX files in the shared directory only
-const SHARED_FOLDER_JS_REGEX = '^(shared).*.(js|jsx)$';
+// include JS and JSX files only in the app, offscreen, shared, and ui directories
+const JS_REGEX = /^(app|offscreen|shared|ui)\/.*\.(js|jsx)$/u;
 
 enum AUTOMATION_TYPE {
   CI = 'ci',
   PRE_COMMIT_HOOK = 'pre-commit-hook',
   PRE_PUSH_HOOK = 'pre-push-hook',
 }
 
-export { EXCLUDE_E2E_TESTS_REGEX, SHARED_FOLDER_JS_REGEX, AUTOMATION_TYPE };
+export { E2E_TESTS_REGEX, JS_REGEX, AUTOMATION_TYPE };

development/fitness-functions/common/shared.test.ts

@@ -30,23 +30,23 @@ describe('filterDiffFileCreations()', (): void => {
     const actualResult = filterDiffFileCreations(testFileDiff);
 
     expect(actualResult).toMatchInlineSnapshot(`
-      "diff --git a/old-file.js b/old-file.js
-      new file mode 100644
-      index 000000000..30d74d258
-      --- /dev/null
-      +++ b/old-file.js
-      @@ -0,0 +1 @@
-      +ping"
+    "diff --git a/old-file.js b/old-file.js
+    new file mode 100644
+    index 000000000..30d74d258
+    --- /dev/null
+    +++ b/old-file.js
+    @@ -0,0 +1 @@
+    +ping"
     `);
   });
 });
 
 describe('hasNumberOfCodeBlocksIncreased()', (): void => {
   it('should show which code blocks have increased', (): void => {
     const testDiffFragment = `
-    +foo
-    +bar
-    +baz`;
+      +foo
+      +bar
+      +baz`;
     const testCodeBlocks = ['code block 1', 'foo', 'baz'];
 
     const actualResult = hasNumberOfCodeBlocksIncreased(
@@ -69,7 +69,7 @@ describe('filterDiffByFilePath()', (): void => {
   it('should return the right diff for a generic matcher', (): void => {
     const actualResult = filterDiffByFilePath(
       testFileDiff,
-      '.*/.*.(js|ts)$|.*.(js|ts)$',
+      /^(.*\/)?.*\.(jsx)$/u, // Exclude jsx files
     );
 
     expect(actualResult).toMatchInlineSnapshot(`
@@ -93,35 +93,17 @@ describe('filterDiffByFilePath()', (): void => {
   });
 
   it('should return the right diff for a specific file in any dir matcher', (): void => {
-    const actualResult = filterDiffByFilePath(testFileDiff, '.*old-file.js$');
+    const actualResult = filterDiffByFilePath(testFileDiff, /.*old-file\.js$/u); // Exclude old-file.js
 
     expect(actualResult).toMatchInlineSnapshot(`
-      "diff --git a/old-file.js b/old-file.js
-      index 57d5de75c..808d8ba37 100644
-      --- a/old-file.js
-      +++ b/old-file.js
-      @@ -1,3 +1,8 @@
-      +ping
-      @@ -34,33 +39,4 @@
-      -pong"
-    `);
-  });
-
-  it('should return the right diff for a multiple file extension (OR) matcher', (): void => {
-    const actualResult = filterDiffByFilePath(
-      testFileDiff,
-      '^(./)*old-file.(js|ts|jsx)$',
-    );
-
-    expect(actualResult).toMatchInlineSnapshot(`
-      "diff --git a/old-file.js b/old-file.js
+      "diff --git a/new-file.ts b/new-file.ts
       index 57d5de75c..808d8ba37 100644
-      --- a/old-file.js
-      +++ b/old-file.js
+      --- a/new-file.ts
+      +++ b/new-file.ts
       @@ -1,3 +1,8 @@
-      +ping
+      +foo
       @@ -34,33 +39,4 @@
-      -pong
+      -bar
       diff --git a/old-file.jsx b/old-file.jsx
       index 57d5de75c..808d8ba37 100644
       --- a/old-file.jsx
@@ -133,10 +115,10 @@ describe('filterDiffByFilePath()', (): void => {
     `);
   });
 
-  it('should return the right diff for a file name negation matcher', (): void => {
+  it('should return the right diff for a multiple file extension (OR) matcher', (): void => {
     const actualResult = filterDiffByFilePath(
       testFileDiff,
-      '^(?!.*old-file.js$).*.[a-zA-Z]+$',
+      /^(\.\/)*old-file\.(js|ts|jsx)$/u, // Exclude files named old-file that have js, ts, or jsx extensions
     );
 
     expect(actualResult).toMatchInlineSnapshot(`
@@ -147,15 +129,25 @@ describe('filterDiffByFilePath()', (): void => {
       @@ -1,3 +1,8 @@
       +foo
       @@ -34,33 +39,4 @@
-      -bar
-      diff --git a/old-file.jsx b/old-file.jsx
-      index 57d5de75c..808d8ba37 100644
-      --- a/old-file.jsx
-      +++ b/old-file.jsx
-      @@ -1,3 +1,8 @@
-      +yin
-      @@ -34,33 +39,4 @@
-      -yang"
+      -bar"
     `);
   });
+
+  it('should return the right diff for a file name negation matcher', (): void => {
+    const actualResult = filterDiffByFilePath(
+      testFileDiff,
+      /^(?!.*old-file\.js$).*\.[a-zA-Z]+$/u, // Exclude files that do not end with old-file.js but include all other file extensions
+    );
+
+    expect(actualResult).toMatchInlineSnapshot(`
+        "diff --git a/old-file.js b/old-file.js
+        index 57d5de75c..808d8ba37 100644
+        --- a/old-file.js
+        +++ b/old-file.js
+        @@ -1,3 +1,8 @@
+        +ping
+        @@ -34,33 +39,4 @@
+        -pong"
+      `);
+  });
 });

development/fitness-functions/common/shared.ts

@@ -1,11 +1,11 @@
-function filterDiffByFilePath(diff: string, regex: string): string {
+function filterDiffByFilePath(diff: string, regex: RegExp): string {
   // split by `diff --git` and remove the first element which is empty
   const diffBlocks = diff.split(`diff --git`).slice(1);
 
   const filteredDiff = diffBlocks
     .map((block) => block.trim())
     .filter((block) => {
-      let didAPathInBlockMatchRegEx = false;
+      let shouldCheckBlock = false;
 
       block
         // get the first line of the block which has the paths
@@ -18,12 +18,13 @@ function filterDiffByFilePath(diff: string, regex: string): string {
         // if at least one of the two paths matches the regex, filter the
         // corresponding diff block in
         .forEach((path) => {
-          if (new RegExp(regex, 'u').test(path)) {
-            didAPathInBlockMatchRegEx = true;
+          if (!regex.test(path)) {
+            // Not excluded, include in check
+            shouldCheckBlock = true;
           }
         });
 
-      return didAPathInBlockMatchRegEx;
+      return shouldCheckBlock;
     })
     // prepend `git --diff` to each block
     .map((block) => `diff --git ${block}`)
@@ -32,6 +33,34 @@ function filterDiffByFilePath(diff: string, regex: string): string {
   return filteredDiff;
 }
 
+function restrictedFilePresent(diff: string, regex: RegExp): boolean {
+  // split by `diff --git` and remove the first element which is empty
+  const diffBlocks = diff.split(`diff --git`).slice(1);
+  let jsOrJsxFilePresent = false;
+  diffBlocks
+    .map((block) => block.trim())
+    .filter((block) => {
+      block
+        // get the first line of the block which has the paths
+        .split('\n')[0]
+        .trim()
+        // split the two paths
+        .split(' ')
+        // remove `a/` and `b/` from the paths
+        .map((path) => path.substring(2))
+        // if at least one of the two paths matches the regex, filter the
+        // corresponding diff block in
+        .forEach((path) => {
+          if (regex.test(path)) {
+            // Not excluded, include in check
+            jsOrJsxFilePresent = true;
+          }
+        });
+      return jsOrJsxFilePresent;
+    });
+  return jsOrJsxFilePresent;
+}
+
 // This function returns all lines that are additions to files that are being
 // modified but that previously already existed. Example:
 // diff --git a/test.js b/test.js
@@ -44,7 +73,9 @@ function filterDiffLineAdditions(diff: string): string {
   const diffLines = diff.split('\n');
 
   const diffAdditionLines = diffLines.filter((line) => {
-    const isAdditionLine = line.startsWith('+') && !line.startsWith('+++');
+    const trimmedLine = line.trim();
+    const isAdditionLine =
+      trimmedLine.startsWith('+') && !trimmedLine.startsWith('+++');
 
     return isAdditionLine;
   });
@@ -108,6 +139,7 @@ function hasNumberOfCodeBlocksIncreased(
 
 export {
   filterDiffByFilePath,
+  restrictedFilePresent,
   filterDiffFileCreations,
   filterDiffLineAdditions,
   hasNumberOfCodeBlocksIncreased,