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deferred.ts
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deferred.ts
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export type Deferred<T = any, R = Error> = {
promise: Promise<T>;
resolve: (t?: T) => void;
reject: (r?: R) => void;
readonly handled: boolean;
};
/** Create deferred promise that can be resolved and rejected by outside */
export function defer<T>(): Deferred<T> {
let handled = false,
resolve,
reject;
const promise = new Promise<T>((res, rej) => {
resolve = r => {
handled = true;
res(r);
};
reject = r => {
handled = true;
rej(r);
};
});
return {
promise,
resolve,
reject,
get handled() {
return handled;
}
};
}
export class DeferredStack<T> {
private _array: Array<T>;
private _queue: Array<Deferred>;
constructor(ls?: Iterable<T>) {
this._array = ls ? [...ls] : [];
this._queue = [];
}
async pop(): Promise<T> {
if (this._array.length > 0) {
return this._array.pop();
}
const d = defer();
this._queue.push(d);
await d.promise;
return this._array.pop();
}
push(value: T): void {
this._array.push(value);
if (this._queue.length > 0) {
const d = this._queue.shift();
d.resolve();
}
}
get size(): number {
return this._array.length;
}
}