queue-promise

queue-promise

queue-promise is a small, dependency-free library for promise-based queues. It will resolve enqueued functions concurrently at a given speed. When a task is being resolved or rejected, an event will be emitted.

Installation

$ npm install queue-promise

Usage

import Queue from "queue-promise";

const queue = new Queue({
  concurrent: 1, // resolve 1 task at a time
  interval: 2000 // resolve a new task once in 2000ms
});

queue.on("resolve", data => console.log(data));
queue.on("reject", error => console.error(error));

queue.push(asyncTaskA); // resolved/rejected after 0s
queue.push(asyncTaskB); // resolved/rejected after 2s
queue.push(asyncTaskC); // resolved/rejected after 4s
queue.push(asyncTaskD); // resolved/rejected after 6s
queue.start();

API

new Queue(options)

Create a new Queue instance.

Option	Default	Description
concurrent	5	How many tasks can be handled at the same time
interval	500	How often should new tasks be handled (in ms)

public .add(task)/.push(task)

Puts a new task on the stack. Throws an error if the provided task is not a valid function.

public .start()

Starts the queue. Queue will use global Promises.

public .started

Whether the queue has been started or not.

public .stop()

Stops the queue.

public .on(event, callback)

Sets a callback for an event. You can set callback for those events: start, stop, tick, resolve, reject, end.

private .next()

Goes to the next request and stops the loop if there is no requests left.

private .remove(key)/.pop(key)/.shift(key)

Removes a task from the queue.

Tests

$ npm test