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

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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

License

ISC

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

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