spiegel-keyman/common/predictive-text/promise-store.ts

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3.4 KiB
TypeScript

/// <reference path="node_modules/es6-shim/es6-shim.min.js" />
/*
* Copyright (c) 2018 National Research Council Canada (author: Eddie A. Santos)
* Copyright (c) 2018 SIL International
*
* Permission is hereby granted, free of charge, to any person obtaining a copy of
* this software and associated documentation files (the "Software"), to deal in
* the Software without restriction, including without limitation the rights to
* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
* the Software, and to permit persons to whom the Software is furnished to do so,
* subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
* FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
* COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
* IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
type Resolve<T> = (value?: T | PromiseLike<T>) => void;
type Reject = (reason?: any) => void;
interface PromiseCallbacks<T> {
resolve: Resolve<T>;
reject: Reject;
}
namespace com.keyman.text.prediction {
/**
* Associate tokens with promises.
*
* First, .make() a promise -- associate a token with resolve/reject callbacks.
*
* You can either .keep() a promise -- resolve() and forget it;
* Or you may also .break() a promise -- reject() and forget it.
*
* <T> is the type of resolved value (value yielded successfully by promise).
*/
export class PromiseStore<T> {
// IE11 offers partial support for new Map().
// Assume only .get(), .set(), .has(), .delete(), and .size work.
// See: http://kangax.github.io/compat-table/es6/#test-Map
private _promises: Map<Token, PromiseCallbacks<T>>;
constructor() {
this._promises = new Map();
}
/**
* How many promises are currently being tracked?
*/
get length(): number {
return this._promises.size;
}
/**
* Associate a token with its respective resolve and reject callbacks.
*/
make(token: Token, resolve: Resolve<T>, reject: Reject): void {
if (this._promises.has(token)) {
return reject(`Existing request with token ${token}`);
}
this._promises.set(token, { reject, resolve });
}
/**
* Resolve the promise associated with a token (with a value!).
* Once the promise is resolved, the token is removed..
*/
keep(token: Token, value: T) {
let callbacks = this._promises.get(token);
if (!callbacks) {
throw new Error(`No promise associated with token: ${token}`);
}
let accept = callbacks.resolve;
this._promises.delete(token);
return accept(value);
}
/**
* Instantly reject and forget a promise associated with the token.
*/
break(token: Token, reason?: any): void {
let callbacks = this._promises.get(token);
if (!callbacks) {
throw new Error(`No promise associated with token: ${token}`);
}
this._promises.delete(token);
callbacks.reject(reason);
}
}
}