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https://github.com/mantoni/listen.js
A tiny library to wait for the results of multiple callbacks. For node and the browser.
https://github.com/mantoni/listen.js
async browser callbacks minimal node thenable
Last synced: 17 days ago
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A tiny library to wait for the results of multiple callbacks. For node and the browser.
- Host: GitHub
- URL: https://github.com/mantoni/listen.js
- Owner: mantoni
- License: mit
- Created: 2012-05-17T18:15:28.000Z (over 12 years ago)
- Default Branch: master
- Last Pushed: 2016-08-17T19:42:31.000Z (about 8 years ago)
- Last Synced: 2024-10-11T15:21:32.566Z (about 1 month ago)
- Topics: async, browser, callbacks, minimal, node, thenable
- Language: JavaScript
- Homepage:
- Size: 50.8 KB
- Stars: 16
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGES.md
- License: LICENSE
Awesome Lists containing this project
README
# listen.js
[![Build Status]](https://travis-ci.org/mantoni/listen.js)
[![SemVer]](http://semver.org)
[![License]](https://github.com/mantoni/listen.js/blob/master/LICENSE)
A tiny library to wait for the results of multiple callbacks. For node and the
browser.
## Install
This will install the `listen` module in your current project and add it to the
`dependencies`:
```
npm install listen --save
```
## Usage
```js
var listen = require('listen');
var listener = listen();
var callbackA = listener();
var callbackB = listener();
/*
* Do async stuff with callbacks.
*
* Callbacks follow the Node.js convention. They expect an error or null as
* the first argument and an optional value as the second:
*
* Fail: callback(new Error('ouch!'));
* Return: callback(null, 'some return value');
*/
listener.then(function (err, values) {
/*
* err - 1) null if no callback received an error
* 2) the error of the callback that received an error
* 3) an error with name ErrorList wrapping multiple errors
*
* values - The non-undefined return values from all callbacks in order of
* callback creation, also exposing names callbacks (see API)
*/
});
```
# API
Start with `var listen = require('listen')`, then use the `listen` function to
create listeners. Use the listeners to create callbacks.
- `listen([values])`: Creates and returns a new listener function. If `values`
are given, it must be an array with initial values.
- `listener([name][, func][, timeout])`: Creates a new callback associated with
the listener. Throws if called after `then`. All arguments are optional and
can be combined.
- `name` exposes the return value of the callback on the values object
under that name.
- `func` gets invoked with `(err, value)` when the callback is invoked.
- `timeout` calls the callback with a `TimeoutError` after the timeout.
- `listener.then(func)`: Invokes the given function once all callbacks where
invoked. If none of the callbacks had errors, the first argument is `null`,
otherwise it's an `Error`. The second argument is the values array in order
of callback creation. Can only be called once.
- `listener.push(value)`: Pushes a value to the internal values array. Throws
if called after `then`.
- `listener.err(error)`: Adds an error to the internal error list. Throws if
called after `then`.
## Compatibility
The `listen` has 100% coverage and runs in these environments:
- Node 0.10, 0.12, 4.3 & 6.3
- IE 9, 10, 11
- Firefox
- Chore
- PhantomJS
## License
MIT
[Build Status]: http://img.shields.io/travis/mantoni/listen.js.svg
[SemVer]: http://img.shields.io/:semver-%E2%9C%93-brightgreen.svg
[License]: http://img.shields.io/npm/l/listen.svg