56 lines
1.6 KiB
TypeScript

export class PromiseCompleter<R> {
promise: Promise<R>;
resolve: (value?: R|PromiseLike<R>) => void;
reject: (error?: any, stackTrace?: string) => void;
constructor() {
this.promise = new Promise((res, rej) => {
this.resolve = res;
this.reject = rej;
});
}
}
export class PromiseWrapper {
static resolve<T>(obj: T): Promise<T> { return Promise.resolve(obj); }
static reject(obj: any, _: any): Promise<any> { return Promise.reject(obj); }
// Note: We can't rename this method into `catch`, as this is not a valid
// method name in Dart.
static catchError<T>(promise: Promise<T>, onError: (error: any) => T | PromiseLike<T>):
Promise<T> {
return promise.catch(onError);
}
static all<T>(promises: (T|Promise<T>)[]): Promise<T[]> {
if (promises.length == 0) return Promise.resolve([]);
return Promise.all(promises);
}
static then<T, U>(
promise: Promise<T>, success: (value: T) => U | PromiseLike<U>,
rejection?: (error: any, stack?: any) => U | PromiseLike<U>): Promise<U> {
return promise.then(success, rejection);
}
static wrap<T>(computation: () => T): Promise<T> {
return new Promise((res, rej) => {
try {
res(computation());
} catch (e) {
rej(e);
}
});
}
static scheduleMicrotask(computation: () => any): void {
PromiseWrapper.then(PromiseWrapper.resolve(null), computation, (_) => {});
}
static isPromise(obj: any): boolean { return obj instanceof Promise; }
static completer<T>(): PromiseCompleter<T> { return new PromiseCompleter<T>(); }
}