@ex1st/tiny-queue

Asynchronous (asyn-await/promise) function queue.

Example

import { Queue } from '@ex1st/tiny-queue';

const queue = new Queue(async function (task) {
  const r = await task;
  return r;
}, { timeout: 2000 });

const result = [];

// add task to the queue
queue.push(new Promise(resolve => {
  setTimeout(() => {
    resolve(1);
  }, 1000);
}));

// add task to the queue
queue.push(new Promise(resolve => {
  setTimeout(() => {
    resolve(2);
  }, 500);
}));

// add task to the queue
queue.push(new Promise(resolve => {
  setTimeout(() => {
    resolve(3);
  }, 100);
}), new Promise(resolve => {
  setTimeout(() => {
    resolve(4);
  }, 50);
}));

// add task to the queue
queue.push(new Promise(resolve => {
  setTimeout(() => {
    resolve(5);
  }, 2500);
}));

queue.on('done', function (res, task) {
  result.push(res);
});

queue.on('timeout', function (task) {
  console.log('task timed out:', task);
});

console.log(queue.running()); // true
console.log(queue.length()); // 4

queue.on('drain', function () {
  console.log(result); // [1,2,3,4]
});

Install

npm install @ex1st/tiny-queue

API

const queue = new Queue(worker, { timeout, filter })

• worker function
• timeout integer, is optional
• filter function, is optional

Instance methods

queue.push(...tasks)

add new task(s) to the queue.

queue.pause()

a function that pauses the processing of tasks.

queue.resume()

a function that resumes the processing of the queued tasks.

queue.kill()

a function that empties remaining tasks from the queue

queue.running()

a function returning execution state of the queue

queue.length()

a function returning the queue's size

queue.setFilter(fn)

a function set a custom filter

Events

queue.on('done', (result, task) => {})

When a task is done.

queue.on('error', (error, task) => {})

When a task throws an error.

queue.on('timeout', (task) => {})

When timeout params milliseconds have elapsed.

queue.on('drain', () => {})

When a last task from a queue has returned from a worker

queue.on('empty', () => {})

When a last task from a queue is given to a worker