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

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

Last synced: 27 days ago
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Modify the value of the specific object's error event

• Host: GitHub
• URL: https://github.com/shinnn/modify-error-event
• Owner: shinnn
• License: unlicense
• Created: 2015-04-26T04:08:53.000Z (over 9 years ago)
• Default Branch: master
• Last Pushed: 2016-09-02T09:48:00.000Z (about 8 years ago)
• Last Synced: 2024-09-18T03:57:52.720Z (about 2 months ago)
• Language: JavaScript
• Size: 9.77 KB
• Stars: 0
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# modify-error-event

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

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

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

[![dependencies Status](https://david-dm.org/shinnn/modify-error-event/status.svg)](https://david-dm.org/shinnn/modify-error-event)

[![devDependencies Status](https://david-dm.org/shinnn/modify-error-event/dev-status.svg)](https://david-dm.org/shinnn/modify-error-event?type=dev)

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

```javascript

const EventEmitter = require('events').EventEmitter;

const modifyErrorEvent = require('modify-error-event');

let emitter = new EventEmitter();

modifyErrorEvent(emitter, err => {

  err.message = 'bar';

  return err;

});

emitter.on('error', err => {

  err.message; //=> 'bar'

});

emitter.emit('error', new Error('foo'));

```

## Installation

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

```

npm install modify-error-event

```

## API

```javascript

const modifyErrorEvent = require('modify-error-event');

```

### modifyErrorEvent(*eventEmitter*, *modifier*)

*eventEmitter*: `Object` (an instance of [`EventEmitter`](https://nodejs.org/api/events.html#events_class_events_eventemitter) or its inheritance e.g. [`Stream`](https://nodejs.org/api/stream.html#stream_stream))  

*modifier*: `Function`  

Return: `Object` (Same as the first argument)

It changes the first argument of the `error` event listeners in response to the return value of the *modifier* function.

```javascript

const EventEmitter = require('events').EventEmitter;

const modifyErrorEvent = require('modify-error-event');

let emitter = new EventEmitter();

modifyErrorEvent(emitter, err => {

  err.message += 'b';

  return err;

});

modifyErrorEvent(emitter, val => {

  err.message += 'c';

  return err;

});

emitter

.on('error', listener)

.emit('error', new Error('a'));

function listener(err) {

  err.message; //=> 'abc'

}

```

## License

[The Unlicense](./LICENSE).