Gazillionth Queue

One in gazillions of task queue implementations.

Constructor

The constructor accepts a (optional) configuration to set concurrency and active_wait values at instantiation.

// instantiate a queue to have up to 2
// dequeued functions active at a time and
// an active wait time of 50 milliseconds
const queue = new GazillionthQueue ({
  concurrency: 2 ,
  active_wait: 50
})

Add to queue

Functions in the queue are executed with a "done" callback argument that should be invoked once the function has completed its work.

• push
• unshift

Push

Add a function to the end of the queue:

queue.push ((done) => {
  // do stuff
  done ()
})

Unshift

Put a function at the start of the queue:

queue.unshift ((done) => {
  // do stuff
  done ()
})

Clear the queue

Clear the queue and return the number of functions cleared. The cleared event will be emitted if there were functions in the queue.

let num_cleared = queue.clear ()

Properties

• concurrency
• active_wait
• started read-only
• length read-only
• active read-only

concurrency

The maximum number of callbacks that should be active at a time.

concurrency is an unsigned integer with a default value of 1.

Setting concurrency to a number value less than 1 pauses the queue. To resume the queue, concurrency should be set to a number value greater than 0.

active_wait

The suggested amount of time to wait, in milliseconds, before dequeueing more functions.

Each time the number of active functions drops below the configured concurrency the queue will wait the time specified by active_wait before filling the concurrency quota.

active_wait is an unsigned integer value with a default value of 16 milliseconds.

started

A read-only boolean flag indicating whether there are functions in the queue or dequeued functions that are still active. Each time done is emitted started will become false again.

length

A read-only count of functions in the queue that are not active.

active

A read-only count of dequeued functions that have been invoked and that have not finished their work by calling done ().

Events

• activated
• cleared
• done
• error

activated

Emitted with an integer representing the count of functions that are dequeued to be invoked, each time functions are dequeued.

cleared

Emitted with an integer representing the count of uncalled functions that were remaining in the queue before clear was called.

done

Emitted each time the queue becomes empty and is not active.

error

Emitted with an error each time a queued function throws an uncaught error.