Fix.

node_modules/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 {
+    private _isReferenceBeingHeld;
+    constructor(value: unknown);
+    isLeaking(): boolean;
+    private _runGarbageCollector;
+    private _isPrimitive;
+}
+//# sourceMappingURL=index.d.ts.map

node_modules/jest-leak-detector/build/index.d.ts.map

@@ -0,0 +1 @@
+{"version":3,"file":"index.d.ts","sourceRoot":"","sources":["../src/index.ts"],"names":[],"mappings":"AAAA;;;;;GAKG;AAMH,MAAM,CAAC,OAAO;IACZ,OAAO,CAAC,qBAAqB,CAAU;gBAE3B,KAAK,EAAE,OAAO;IAiC1B,SAAS,IAAI,OAAO;IAMpB,OAAO,CAAC,oBAAoB;IAa5B,OAAO,CAAC,YAAY;CAGrB"}

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

@@ -0,0 +1,118 @@
+'use strict';
+
+Object.defineProperty(exports, '__esModule', {
+  value: true
+});
+exports.default = void 0;
+
+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 _prettyFormat() {
+  const data = _interopRequireDefault(require('pretty-format'));
+
+  _prettyFormat = function _prettyFormat() {
+    return data;
+  };
+
+  return data;
+}
+
+function _interopRequireDefault(obj) {
+  return obj && obj.__esModule ? obj : {default: obj};
+}
+
+function _defineProperty(obj, key, value) {
+  if (key in obj) {
+    Object.defineProperty(obj, key, {
+      value: value,
+      enumerable: true,
+      configurable: true,
+      writable: true
+    });
+  } else {
+    obj[key] = value;
+  }
+  return obj;
+}
+
+class _default {
+  constructor(value) {
+    _defineProperty(this, '_isReferenceBeingHeld', void 0);
+
+    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;