versatica / awaitqueue

JavaScript utility to enqueue async tasks for Node.js and the browser

AwaitQueue

JavaScript 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

new AwaitQueue()

Creates an AwaitQueue instance.

awaitQueue.size: number

Number of enqueued pending tasks.

async awaitQueue.push(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 returned by the given task.

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

awaitQueue.stop(): void

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

awaitQueue.remove(taskIdx: number): void

Removes the pending task with given index. The task is rejected with an instance of AwaitQueueRemovedTaskError.

• @param taskIdx: Index of the pending task to be removed.

awaitQueue.dump(): AwaitQueueTaskDump[]

Returns an array with information about pending tasks in the queue. See the AwaitQueueTaskDump type above.

Usage example

See test.ts file.

Author

• Iñaki Baz Castillo [website|github]

License

ISC

awaitqueue's Issues

'awaitqueue' reports an error after upgrading to version 3. There is no problem with version 2.

'awaitqueue' reports an error after upgrading to version 3. There is no problem with version 2.

ERROR in ./node_modules/mediasoup-client/node_modules/awaitqueue/lib/index.js 12:23
Module parse failed: Unexpected token (12:23)
You may need an appropriate loader to handle this file type, currently no loaders are configured to process this file. See https://webpack.js.org/concepts#loaders
| class AwaitQueueStoppedError extends Error {
| constructor(message) {

    super(message ?? 'AwaitQueue stopped');

| this.name = 'AwaitQueueStoppedError';
| // @ts-ignore

Allow to pass arguments to task

At

awaitqueue/src/index.ts

Line 101 in 1eee814

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

, allow to have arguments after name that will be passed as arguments to the call of the task when executed. This would allow to pass it parameters without needing to use nested functions and get them from closures.

ES6 import AwaitQueue from 'awaitqueue'; does not work

It should work given that the main module exports a class as follows:

module.exports = AwaitQueue;

However, when using browserify + babel or jest, it fails with:

awaitqueue_1.default is not a constructor