Migrate jest-leak-detector to TypeScript

CHANGELOG.md

@@ -11,6 +11,7 @@
 - `[diff-sequences]`: Migrate to Typescript ([#7820](https://github.com/facebook/jest/pull/7820))
 - `[jest-get-type]`: Migrate to TypeScript ([#7818](https://github.com/facebook/jest/pull/7818))
 - `[jest-regex-util]`: Migrate to TypeScript ([#7822](https://github.com/facebook/jest/pull/7822))
+- `[jest-leak-detector]`: Migrate to TypeScript ([#7825](https://github.com/facebook/jest/pull/7825))
 
 ### Performance
 

packages/jest-leak-detector/build/index.d.ts

@@ -0,0 +1,14 @@
+/**
+ * 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.
+ */
+export default class {
+    _isReferenceBeingHeld: boolean;
+    constructor(value: any);
+    isLeaking(): boolean;
+    _runGarbageCollector(): void;
+    _isPrimitive(value: any): boolean;
+}
+//# sourceMappingURL=index.d.ts.map

packages/jest-leak-detector/build/index.js

@@ -0,0 +1,108 @@
+/**
+ * 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.
+ */
+'use strict';
+
+Object.defineProperty(exports, '__esModule', {
+  value: true
+});
+exports.default = void 0;
+
+function _prettyFormat() {
+  const data = _interopRequireDefault(require('pretty-format'));
+
+  _prettyFormat = function _prettyFormat() {
+    return data;
+  };
+
+  return data;
+}
+
+function _v() {
+  const data = _interopRequireDefault(require('v8'));
+
+  _v = function _v() {
+    return data;
+  };
+
+  return data;
+}
+
+function _vm() {
+  const data = _interopRequireDefault(require('vm'));
+
+  _vm = function _vm() {
+    return data;
+  };
+
+  return data;
+}
+
+function _interopRequireDefault(obj) {
+  return obj && obj.__esModule ? obj : {default: obj};
+}
+
+class _default {
+  constructor(value) {
+    if (this._isPrimitive(value)) {
+      throw new TypeError(
+        [
+          'Primitives cannot leak memory.',
+          'You passed a ' +
+            typeof value +
+            ': <' +
+            (0, _prettyFormat().default)(value) +
+            '>'
+        ].join(' ')
+      );
+    }
+
+    let weak;
+
+    try {
+      // eslint-disable-next-line import/no-extraneous-dependencies
+      weak = require('weak');
+    } catch (err) {
+      if (!err || err.code !== 'MODULE_NOT_FOUND') {
+        throw err;
+      }
+
+      throw new Error(
+        'The leaking detection mechanism requires the "weak" package to be installed and work. ' +
+          'Please install it as a dependency on your main project'
+      );
+    }
+
+    weak(value, () => (this._isReferenceBeingHeld = false));
+    this._isReferenceBeingHeld = true; // Ensure value is not leaked by the closure created by the "weak" callback.
+
+    value = null;
+  }
+
+  isLeaking() {
+    this._runGarbageCollector();
+
+    return this._isReferenceBeingHeld;
+  }
+
+  _runGarbageCollector() {
+    const isGarbageCollectorHidden = !global.gc; // GC is usually hidden, so we have to expose it before running.
+
+    _v().default.setFlagsFromString('--expose-gc');
+
+    _vm().default.runInNewContext('gc')(); // The GC was not initially exposed, so let's hide it again.
+
+    if (isGarbageCollectorHidden) {
+      _v().default.setFlagsFromString('--no-expose-gc');
+    }
+  }
+
+  _isPrimitive(value) {
+    return value !== Object(value);
+  }
+}
+
+exports.default = _default;

packages/jest-leak-detector/src/index.js → packages/jest-leak-detector/build/index.ts_

@@ -3,8 +3,6 @@
  *
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
- *
- * @flow
  */
 
 'use strict';

packages/jest-leak-detector/package.json

@@ -8,6 +8,7 @@
   },
   "license": "MIT",
   "main": "build/index.js",
+  "types": "build/index.d.ts",
   "dependencies": {
     "pretty-format": "^24.0.0"
   },

packages/jest-leak-detector/src/__tests__/index.test.js → packages/jest-leak-detector/src/__tests__/index.test.ts

@@ -73,8 +73,8 @@ it('tests different objects', () => {
 });
 
 it('correctly checks more complex leaks', () => {
-  let ref1 = {};
-  let ref2 = {};
+  let ref1: any = {};
+  let ref2: any = {};
 
   // Create a circular dependency between ref1 and ref2.
   ref1.ref2 = ref2;

packages/jest-leak-detector/src/index.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.
+ */
+
+'use strict';
+
+import v8 from 'v8';
+import vm from 'vm';
+import prettyFormat from 'pretty-format';
+
+export default class {
+  _isReferenceBeingHeld: boolean;
+
+  constructor(value: any) {
+    if (this._isPrimitive(value)) {
+      throw new TypeError(
+        [
+          'Primitives cannot leak memory.',
+          'You passed a ' + typeof value + ': <' + prettyFormat(value) + '>',
+        ].join(' '),
+      );
+    }
+
+    let weak;
+
+    try {
+      // eslint-disable-next-line import/no-extraneous-dependencies
+      weak = require('weak');
+    } catch (err) {
+      if (!err || err.code !== 'MODULE_NOT_FOUND') {
+        throw err;
+      }
+
+      throw new Error(
+        'The leaking detection mechanism requires the "weak" package to be installed and work. ' +
+          'Please install it as a dependency on your main project',
+      );
+    }
+
+    weak(value, () => (this._isReferenceBeingHeld = false));
+    this._isReferenceBeingHeld = true;
+
+    // Ensure value is not leaked by the closure created by the "weak" callback.
+    value = null;
+  }
+
+  isLeaking(): boolean {
+    this._runGarbageCollector();
+
+    return this._isReferenceBeingHeld;
+  }
+
+  _runGarbageCollector() {
+    const isGarbageCollectorHidden = !global.gc;
+
+    // GC is usually hidden, so we have to expose it before running.
+    v8.setFlagsFromString('--expose-gc');
+    vm.runInNewContext('gc')();
+
+    // The GC was not initially exposed, so let's hide it again.
+    if (isGarbageCollectorHidden) {
+      v8.setFlagsFromString('--no-expose-gc');
+    }
+  }
+
+  _isPrimitive(value: any): boolean {
+    return value !== Object(value);
+  }
+}

packages/jest-leak-detector/tsconfig.json

@@ -0,0 +1,7 @@
+{
+  "extends": "../../tsconfig.json",
+  "compilerOptions": {
+    "rootDir": "src",
+    "outDir": "build"
+  }
+}