a promise queue

 

This is just another promise queue. Simple.

+ Native es6
+ With concurrency
+ Optional retry attempts for failed promises
+ Option to use your favourite promise flavour (Bluebird, Q)

Install

You know this:
``
npm install a-promise-queue --save
`

Interface

+ queue = new PromiseQueue([options], [Function callback])
Callback is fired whenever queue is emptied. If callback is not provided, queue will act as a promise which is resolved once queue is finished.
Options:
`
{
promise: Promise, // the type of promises used. defaults to es6 native promises,
concurrency: Number // set the number of promises to run in parallel.
}
`

+ queue.length
Returns number of promises waiting to be executed.

+ var promise = queue.add(Function generator, [Object options])
Returns a promise which is resolved or rejected when the promise produced by the generator is eventually resolved.
Example options:
`js
{
attempts: number, // if promise fails it will retry this many times.
priority: number, // execution is ordered by priority default = 0.
}
`

+ var promise = queue.flush()
Runs all promises currently in the queue concurrently.
Returns a promise which is resolved when all promises are finished.
Any promises added after .flush() will execute after flush is complete.

Example:

`js
var PromiseQueue = require('a-promise-queue');

var delay = (ms) => () => new Promise(resolve => setTimeout(resolve, ms));

var queue = new PromiseQueue(() => console.log('Queue is empty'));
queue.add(delay(100)).then(() => console.log('first this'));
queue.add(() => Promise.reject('then this fails')).catch((e) => console.log('Errored:', e));
queue.add(delay(10)).then(() => console.log('and this succeeds'));
queue.add(delay(10), { priority: 1 }).then(() => console.log('but not before this one jumps the queue.'));
``