type DeferredPromiseOptions<T> = {
timeout?: number;
onTimeout?: (resolve: (value: T) => void, reject: (reason: Error) => void) => void;
};
/** Creates a promise and exposes its resolve and reject methods, with an optional timeout. */
export class DeferredPromise<T> extends Promise<T> {
resolve: (value: T) => void;
reject: (reason: unknown) => void;
private timeoutId?: NodeJS.Timeout;
constructor(
executor: (resolve: (value: T) => void, reject: (reason: Error) => void) => void,
{ timeout, onTimeout }: DeferredPromiseOptions<T> = {}
) {
let resolveFn: (value: T) => void;
let rejectFn: (reason?: unknown) => void;
super((resolve, reject) => {
resolveFn = resolve;
rejectFn = reject;
});
// eslint-disable-next-line @typescript-eslint/no-non-null-assertion
this.resolve = resolveFn!;
// eslint-disable-next-line @typescript-eslint/no-non-null-assertion
this.reject = rejectFn!;
if (timeout !== undefined && onTimeout) {
this.timeoutId = setTimeout(() => {
onTimeout(this.resolve, this.reject);
}, timeout);
}
executor(
(value: T) => {
if (this.timeoutId) clearTimeout(this.timeoutId);
this.resolve(value);
},
(reason: Error) => {
if (this.timeoutId) clearTimeout(this.timeoutId);
this.reject(reason);
}
);
}
static fromPromise<T>(promise: Promise<T>, options: DeferredPromiseOptions<T> = {}): DeferredPromise<T> {
return new DeferredPromise<T>((resolve, reject) => {
promise
.then((value) => {
resolve(value);
})
.catch((reason) => {
reject(reason as Error);
});
}, options);
}
}
