53 lines
1.4 KiB
Plaintext
53 lines
1.4 KiB
Plaintext
/**
|
|
* Copyright (c) 2013-present, Facebook, Inc.
|
|
*
|
|
* This source code is licensed under the MIT license found in the
|
|
* LICENSE file in the root directory of this source tree.
|
|
*
|
|
* @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; |