YQueue

Yet another concurrent priority task queue, yay!

Install

npm install yqueue

Features

• Concurrency control
• Prioritized tasks
• Error handling for batch tasks
• Best effort for error stack trace
• Work with async hooks

API

YQueue(options?)

Returns a new queue instance.

options

Type: object

concurrency

Type: number
Default: 10
Minimum: 1

Concurrency limit.

queue

YQueue instance.

.run(fn, options?)

Adds a sync or async task to the queue. Always returns a promise.

Note: If your items can potentially throw an exception, you must handle those errors from the returned Promise or they may be reported as an unhandled Promise rejection and potentially cause your process to exit immediately.

fn

Type: Function

Promise-returning/async function.

options

Type: object

priority

Type: number
Default: 0

Priority of operation. Operations with greater priority will be scheduled first.

.add(fn, options?)

Adds a sync or async task to the queue. The only difference from run is that it returns nothing.

.onIdle()

Returns a promise that settles when the queue becomes empty, and all promises have completed.

.onQueueSizeLessThan(limit)

Returns a promise that settles when the queue size is less than the given limit.

If you want to avoid having the queue grow beyond a certain size you can await queue.onQueueSizeLessThan(size) before adding a new item.

Note that this only limits the number of items waiting to start. There could still be up to concurrency jobs already running that this call does not include in its calculation.

YBatch(options?)

Returns a new batch instance.

options

Type: object

concurrency

Type: number
Default: 10
Minimum: 1

Concurrency limit.

maxQueueLength

Type: number
Default: the value of concurrency
Minimum: 1

Wait until queue size is less than this limit before adding new tasks.

batch

YBatch instance.

.add(fn, options?)

Adds a sync or async task to the batch. Always returns a promise, which will be settled once the queue size is less than maxQueueLength limit and the task added to the queue.

fn

Type: Function

Promise-returning/async function.

options

Type: object

priority

Type: number
Default: 0

Priority of operation. Operations with greater priority will be scheduled first.

.failFast()

Returns a promise that settles when any of the tasks throws an error or all tasks have completed.

.allSettled(limit)

Returns a promise that settles when all tasks have completed, all promise rejections from the tasks will be wrapped as a YBatchErrors class, which put all errors in the errors field.