Awaitqueue NPM

AwaitQueue

TypeScript utility to enqueue asynchronous tasks and run them sequentially one after another. For Node.js and the browser.

Installation

npm install awaitqueue

Usage

In ES6:

import {
	AwaitQueue,
	AwaitQueueTask,
	AwaitQueueTaskDump,
	AwaitQueueStoppedError,
	AwaitQueueRemovedTaskError,
} from 'awaitqueue';

In CommonJS:

const {
	AwaitQueue,
	AwaitQueueTask,
	AwaitQueueTaskDump,
	AwaitQueueStoppedError,
	AwaitQueueRemovedTaskError,
} = require('awaitqueue');

Types

`type AwaitQueueTask`

type AwaitQueueTask<T> = () => T | PromiseLike<T>;

TypeScript type representing a function that returns a value T or a Promise that resolves with T.

`type AwaitQueueTaskDump`

type AwaitQueueTaskDump = {
	idx: number;
	task: AwaitQueueTask<unknown>;
	name?: string;
	enqueuedTime: number;
	executionTime: number;
};

TypeScript type representing an item in the array returned by the awaitQueue.dump() method.

idx: Index of the pending task in the queue (0 means the task being processed now).
task: The function to be executed.
name: The name of the given function (if any) or the name argument given to awaitQueue.push() method (if any).
enqueuedTime: Time in milliseconds since the task was enqueued, this is, since awaitQueue.push() was called until its execution started or until now if not yet started.
executionTime: Time in milliseconds since the task execution started (or 0 if not yet started).

API

Class `AwaitQueue`

const awaitQueue = new AwaitQueue();

Getter `awaitQueue.size`

size: number;

Number of enqueued pending tasks in the queue (including the running one if any).

Method `awaitQueue.push()`

async push<T>(task: AwaitQueueTask<T>, name?: string): Promise<T>

Accepts a task as argument and enqueues it after pending tasks. Once processed, the push() method resolves (or rejects) with the result (or error) returned by the given task.

@param task: Asynchronous or asynchronous function.
@param name: Optional task name (useful for awaitQueue.dump() method).

Method `awaitQueue.stop()`

stop(): void

Makes all pending tasks reject with an instance of AwaitQueueStoppedError. The AwaitQueue instance is still usable for future tasks added via push() method.