core-queue

Simple, zero dependency, promise-based queue.

Package is under development. API might change.

Features

• Promise based queue.
• Concurrency.
• Build-in flow control methods.

Installation

Via npm:

npm install core-queue

Via yarn:

yarn add core-queue

Loading the module

import { CoreQueue, CoreQueueOptions } from "core-queue";

Common usage

Create options

const options: CoreQueueOptions = {
  maxConcurrency: 1,
  maxTasks: 10,
  autostart: true
};

Create queue

const coreQueue: CoreQueue = new CoreQueue(options);

Add async task and handle result with promises

coreQueue
  .enqueue(() => someTask())
  .then(result => {})
  .catch(error => {});

Add async task and await result

try { 
  await coreQueue.enqueue(() => someTask());
}catch(error){
  // handle error
}

Await until every task is settled (resolved or rejected)

await coreQueue.done();

API

CoreQueue(options)

Returns new CoreQueue instance.

Getters

size number

• Returns sum of tasks awaiting in queue and tasks which are currently in progress.

pendingSize number

• Returns number of tasks in queue.

inProgressSize number

• Returns number of tasks which currently beign executed.

isEmpty boolean

• Returns true if the number of awaiting tasks is zero.

isFull boolean

• Returns true if the options limit is exceeded.
• Is calculated as pedningTasks + awaitingTasks.

peek

• Returns first element without removing it.
• Returns null if queue is empty.

Methods

start()

• Start task execution (Have to be called if autostart is set to false).
• Could be called after stop()

stop()

• Stop task execution.
• Task that was already started will settle.

clear()

• Removes all pending tasks.

done() promise

• Resolves after all tasks are settled and queue is empty.

enqueue(()=> {})

• Add new async task into queue.
• Throws error if maxTasks is exceeded.

CoreQueueOptions

maxTasks number

• Maximum of pending and idle tasks in queue.

maxConcurrency number

• Maximum of concurrently executed tasks.

autostart boolean

• Specify if tasks should be resolved as soon as possible.
• If set to false, then start() have to be called.

License

MIT