@naturalcycles/js-lib/dist/asyncManager.d.ts

Standard library for universal (browser + Node.js) javascript

import type { CommonLogger } from './log/commonLogger.js';
import type { NumberOfMilliseconds } from './types.js';
declare class AsyncManagerImpl {
    logger: CommonLogger;
    pendingOps: Set<Promise<unknown>>;
    private onErrorHooks;
    runInBackground(promise: Promise<unknown>): void;
    onError(fn: OnErrorHook): void;
    /**
     * Resolves when all pending operations settle.
     * They may resolve or reject, allDone will never throw.
     * Errors (rejections) are reported to onErrorHooks (instead).
     *
     * If timeout is specified - it resolves if timeout has reached.
     */
    allDone(timeout?: NumberOfMilliseconds): Promise<void>;
    reset(): void;
    private fireOnErrorHooks;
}
/**
 * Singleton which keeps track of async operations - "voided promise-returning functions"
 * that should run in parallel to the main request.
 *
 * It is an alternative to do `void doSomeAnalytics()`, which should run in parallel
 * and not block the request (not slow down nor fail the request on analytics api failure).
 *
 * At the same time, `void doSomeAnalytics()` gets completely detached and untracked,
 * nothing awaits it, its rejection becomes unhandledRejection (and may kill Node.js process).
 *
 * With AsyncManager, you instead register all those "voided" calls like this:
 *
 * AsyncManager.runInBackground(doSomeAnalytics())
 *
 * Then, in a few places you may be interested to ensure that all async operations have been finished.
 * The places can be:
 * - Graceful shutdown of a backend service
 * - Before the end of runScript
 * - At the end of each unit test, to make sure async ops don't leak
 *
 * You ensure no pending async operations like this:
 *
 * await AsyncManager.allDone()
 *
 * which never throws, but instead awaits all operations to be settled.
 *
 * @experimental
 */
export declare const AsyncManager: AsyncManagerImpl;
export declare const runInBackground: (promise: Promise<unknown>) => void;
export type OnErrorHook = (err: Error) => any;
export {};