https://github.com/shinnn/modify-event

Modify the value of the specific object's event
https://github.com/shinnn/modify-event

Last synced: 26 days ago
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Modify the value of the specific object's event

• Host: GitHub
• URL: https://github.com/shinnn/modify-event
• Owner: shinnn
• License: mit
• Created: 2014-04-20T05:56:47.000Z (over 10 years ago)
• Default Branch: master
• Last Pushed: 2019-01-10T01:47:40.000Z (almost 6 years ago)
• Last Synced: 2024-10-13T03:11:00.635Z (about 1 month ago)
• Language: JavaScript
• Homepage:
• Size: 89.8 KB
• Stars: 6
• Watchers: 1
• Forks: 3
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# modify-event

[![npm version](https://img.shields.io/npm/v/modify-event.svg)](https://www.npmjs.com/package/modify-event)

[![Build Status](https://travis-ci.com/shinnn/modify-event.svg?branch=master)](https://travis-ci.com/shinnn/modify-event)

[![Coverage Status](https://img.shields.io/coveralls/shinnn/modify-event.svg)](https://coveralls.io/github/shinnn/modify-event)

Modify the value of the specific object's [event](https://nodejs.org/api/events.html)

```javascript

const {EventEmitter} = require('events');

const modifyEvent = require('modify-event');

const emitter = new EventEmitter();

modifyEvent(emitter, 'foo', val => val * 2);

emitter.on('foo', data => {

  data; //=> 2

});

emitter.emit('foo', 1);

```

## Installation

[Use](https://docs.npmjs.com/cli/install) [npm](https://docs.npmjs.com/about-npm/).

```

npm install modify-event

```

## API

```javascript

const modifyEvent = require('modify-event');

```

### modifyEvent(*eventEmitter*, *eventName*, *modifier*)

*eventEmitter*: [`EventEmitter`](https://nodejs.org/api/events.html#events_class_eventemitter)  

*eventName*: `string` `symbol` (event name)  

*modifier*: `Function`  

Return: `EventEmitter` (a reference to the first argument)

It changes the first argument of the event listeners for a given event, in response to the return value of the *modifier* function.

```javascript

const {EventEmitter} = require('events');

const modifyEvent = require('modify-event');

const emitter = new EventEmitter();

const eventName = Symbol('custom event name');

modifyEvent(emitter, eventName, val => `${val}b`);

modifyEvent(emitter, eventName, val => `${val}c`);

emitter

.on(eventName, listener)

.emit(eventName, 'a');

function listener(data) {

  data; //=> 'abc'

}

```

## License

Copyright (c) 2015 - 2019 [Shinnosuke Watanabe](https://github.com/shinnn)

Licensed under [the MIT License](./LICENSE).