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diff --git a/node_modules/fbjs/lib/PromiseMap.js.flow b/node_modules/fbjs/lib/PromiseMap.js.flow
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+/**
+ * Copyright (c) 2013-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ *
+ * @providesModule PromiseMap
+ * @flow
+ */
+
+'use strict';
+
+const Deferred = require('./Deferred');
+
+const invariant = require('./invariant');
+
+/**
+ * A map of asynchronous values that can be get or set in any order. Unlike a
+ * normal map, setting the value for a particular key more than once throws.
+ * Also unlike a normal map, a key can either be resolved or rejected.
+ */
+class PromiseMap<Tvalue, Treason> {
+  _deferred: { [key: string]: Deferred<any, any> };
+
+  constructor() {
+    this._deferred = {};
+  }
+
+  get(key: string): Promise<any> {
+    return getDeferred(this._deferred, key).getPromise();
+  }
+
+  resolveKey(key: string, value: Tvalue): void {
+    const entry = getDeferred(this._deferred, key);
+    invariant(!entry.isSettled(), 'PromiseMap: Already settled `%s`.', key);
+    entry.resolve(value);
+  }
+
+  rejectKey(key: string, reason: Treason): void {
+    const entry = getDeferred(this._deferred, key);
+    invariant(!entry.isSettled(), 'PromiseMap: Already settled `%s`.', key);
+    entry.reject(reason);
+  }
+}
+
+function getDeferred(entries: { [key: string]: Deferred<any, any> }, key: string): Deferred<any, any> {
+  if (!entries.hasOwnProperty(key)) {
+    entries[key] = new Deferred();
+  }
+  return entries[key];
+}
+
+module.exports = PromiseMap;
+\ No newline at end of file