Implementation of a promise-based FIFO queuing system using ES2017 async generators.
npm install orderly-queue> Implementation of a promise-based FIFO queuing system using ES2017 async generators.
!Travis
!npm
!License MIT
> npm: npm i orderly-queue -S
> Babel: babel-plugin-syntax-async-generators
* Takes a function that returns a promise (or Promise.all)
* Invokes the promise and yields the eventual result
* Awaits the completion of the task before beginning the next
* Implements a pseudo-observable for next and error
* Passes the returned props along to the next task
``javascript
import Queue from 'orderly-queue';
const queue = Queue({ value: ['Blueberries'], next: console.log });
queue.process(fruits => Promise.resolve([...fruits, 'Apples']));
queue.process(fruits => Promise.resolve([...fruits, 'Bananas']));
queue.process(fruits => Promise.resolve([...fruits, 'Raspberries']));
// > ['Blueberries']
// > ['Blueberries', 'Apples']
// > ['Blueberries', 'Apples', 'Bananas']
// > ['Blueberries', 'Apples', 'Bananas', 'Raspberries']
`
Each task will wait before the completion of the current task, meaning you can safely assume the order of fruits no matter how long it takes for a single task to complete.
Any errors that are raised will be passed to the error function, however the items in the queue will continue to be invoked one-at-a-time passing in the props from the last successful invocation.
`javascript
import Queue from 'orderly-queue';
const queue = Queue({ value: ['Blueberries'], next: console.log, error: console.log });
queue.process(fruits => Promise.resolve([...fruits, 'Apples']));
queue.process(fruits => Promise.reject('Error: Fruitless...'));
queue.process(fruits => Promise.resolve([...fruits, 'Bananas']));
queue.process(fruits => Promise.resolve([...fruits, 'Raspberries']));
// > ['Blueberries']
// > ['Blueberries', 'Apples']
// > Error: Fruitless...
// > ['Blueberries', 'Apples', 'Bananas']
// > ['Blueberries', 'Apples', 'Bananas', 'Raspberries']
`
In cases where you wish to end the iterator early you can invoke the abort method — perhaps in response to an error being raised. Any queued tasks will not be run.
`javascript
const queue = Queue({ value: ['Blueberries'], next: console.log, error: console.log });
// ...
queue.abort();
``