# event-to-promise
> Create a promise waiting for an event
Latest version **0.8.0** (published 2017-03-01) · MIT license · 0 weekly downloads
> **Deprecated.** This package is deprecated.
## Install
```sh
npm install event-to-promise
pnpm add event-to-promise
yarn add event-to-promise
bun add event-to-promise
```
## Health
**Score 10/100 (F)** — status: deprecated.
Negative: deprecated.
## Facts
| | |
|---|---|
| Version | 0.8.0 |
| Published | 2017-03-01 |
| First published | 2014-04-13 |
| Weekly downloads | 0 |
| License | MIT |
| TypeScript types | separate (@types/event-to-promise) |
| Module format | CommonJS |
| Dependencies | 0 |
| Known vulnerabilities | 0 |
| Install scripts | no |
| GitHub stars | 35 |
| Author | Julien Fontanet |
| Maintainers | julien-f, marsaud |
| Keywords | event, promise |
## Links
- npm: https://www.npmjs.com/package/event-to-promise
- Repository: https://github.com/JsCommunity/event-to-promise
- Issues: https://github.com/JsCommunity/event-to-promise/issues
- npm.io page: https://npm.io/package/event-to-promise
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## Recent versions
- 0.8.0 (latest) — 2017-03-01
- 0.7.0 — 2016-02-10
- 0.6.0 — 2015-12-01
- 0.5.0 — 2015-11-30
- 0.4.0 — 2015-08-24
- 0.3.3 — 2015-05-24
- 0.3.2 — 2014-10-08
- 0.3.1 — 2014-07-31
- 0.3.0 — 2014-06-09
- 0.2.4 — 2014-05-22
- 0.2.3 — 2014-05-18
- 0.2.2 — 2014-04-19
- 0.2.1 — 2014-04-16
- 0.2.0 — 2014-04-15
- 0.1.0 — 2014-04-13
## README
# event-to-promise
[](http://travis-ci.org/JsCommunity/event-to-promise)
[](https://david-dm.org/JsCommunity/event-to-promise)
[](https://david-dm.org/JsCommunity/event-to-promise#info=devDependencies)
> Create a promise waiting for an event
## Installation
### Node & [Browserify](http://browserify.org/)/[Webpack](https://webpack.js.org/)
Installation of the [npm package](https://npmjs.org/package/event-to-promise):
```
> npm install --save event-to-promise
```
Then require the package:
```javascript
var eventToPromise = require('event-to-promise');
```
### Browser
You can directly use the build provided at [unpkg.com](https://unpkg.com):
```html
```
## Example
```javascript
function createServer (port) {
var server = require('http').createServer()
server.listen(port)
// The server will be returned once it has started listening.
//
// If an error happened, it will be forwarded instead.
return eventToPromise(server, 'listening').then(function () {
return server
})
}
// Using plain promise.
createServer(80).then(function (server) {
console.log('Server listening on http://localhost:80/')
}).catch(function (error) {
console.error('Server could not start:', error)
})
```
Event better using [ES2016 asynchronous functions](https://github.com/tc39/ecmascript-asyncawait):
```js
async function createServer (port) {
var server = require('http').createServer()
server.listen(port)
await eventToPromise(server, 'listening')
return server
}
async function main () {
try {
const server = await createServer(80);
console.log('Server listening on http://localhost:80/');
} catch (error) {
console.error('Server could not start:', error);
}
}
main()
```
## API
This library requires promises support, for Node versions prior to 0.12 [see
this page](https://github.com/JsCommunity/js-promise-toolbox#usage) to
enable them.
### eventToPromise(emitter, event, [options]) => Promise
> Wait for one event. The first parameter of the emitted event is used
> to resolve/reject the promise.
The returned promise has a `cancel()` method which can be used to
remove the event listeners. Note that the promise will never settled
if canceled.
```js
const promise = eventToPromise(emitter, 'foo')
promise.cancel()
```
#### emitter
*Required*
Type: `Object`
The event emitter you want to watch an event on.
#### event
*Required*
Type: `string`
The name of the event you want to watch.
#### options
##### array
Type: `boolean`
Default: `false`
If true, all parameters of the emitted events are put in an array which is used to resolve/reject the promise.
##### error
Type: `string`
Default: `"error"`
The name of the event which rejects the promise.
##### ignoreErrors
Type: `boolean`
Default: `false`
Whether the error event should be ignored and not reject the promise.
### eventToPromise.multi(emitter, successEvents, errorEvents) => Promise
> Wait for one of multiple events. The array of all the parameters of
> the emitted event is used to resolve/reject the promise.
>
> The array also has an `event` property indicating which event has
> been emitted.
The returned promise has a `cancel()` method which can be used to
remove the event listeners. Note that the promise will never settled
if canceled.
```js
const promise = eventToPromise(emitter, 'foo')
promise.cancel()
```
#### emitter
*Required*
Type: `Object`
The event emitter you want to watch an event on.
#### successEvents
*Required*
Type: `Array`
The names of the events which resolve the promise.
#### errorEvents
Type: `Array`
Default: `[ 'error' ]`
The names of the events which reject the promise.
## Contributing
Contributions are *very* welcome, either on the documentation or on
the code.
You may:
- report any [issue](https://github.com/JsCommunity/event-to-promise/issues)
you've encountered;
- fork and create a pull request.
## License
ISC © [Julien Fontanet](http://julien.isonoe.net)
---
_Source: https://npm.io/package/event-to-promise · Machine-readable twin of the npm.io package page. Health data is recomputed on every publish._