https://github.com/wildhoney/orderlyqueue

Implementation of a promise-based FIFO queuing system using ES2017 async generators.
https://github.com/wildhoney/orderlyqueue

async asynchronous await consecutive consecutively fifo observable promise promises queue task yield

Last synced: 2 months ago
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Implementation of a promise-based FIFO queuing system using ES2017 async generators.

• Host: GitHub
• URL: https://github.com/wildhoney/orderlyqueue
• Owner: Wildhoney
• License: mit
• Created: 2016-11-07T22:48:39.000Z (about 8 years ago)
• Default Branch: master
• Last Pushed: 2017-01-20T09:06:25.000Z (almost 8 years ago)
• Last Synced: 2024-10-05T12:28:25.882Z (3 months ago)
• Topics: async, asynchronous, await, consecutive, consecutively, fifo, observable, promise, promises, queue, task, yield
• Language: JavaScript
• Size: 62.5 KB
• Stars: 3
• Watchers: 4
• Forks: 1
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# Orderly Queue

![Bus Queue](/media/bus-queue.jpg)

> Implementation of a promise-based FIFO queuing system using ES2017 async generators.

![Travis](http://img.shields.io/travis/Wildhoney/OrderlyQueue.svg?style=flat-square)

 

![npm](http://img.shields.io/npm/v/orderly-queue.svg?style=flat-square)

 

![License MIT](http://img.shields.io/badge/License-MIT-lightgrey.svg?style=flat-square)

> **npm:** `npm i orderly-queue -S`


> **Babel:** [`babel-plugin-syntax-async-generators`](https://www.npmjs.com/package/babel-plugin-syntax-async-generators)

* Takes a function that returns a promise (or `Promise.all`)

* Invokes the promise and `yield`s 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

# Usage

```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.

## Errors

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();

```