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Michael Di Prisco
Michael Di Prisco

Posted on • Updated on

My Journey in Open Source - event-emitter

Link to the repo

What is this?

This is a function which returns a simple EventEmitter.

It is a simpler implementation of the EventEmitter class from NodeJS.

It is not meant to be a replacement for the NodeJS EventEmitter, but rather a simple alternative for those who don't want to use the NodeJS EventEmitter.

It is also a good way to learn how Event Emitting works as a concept.

How do I install it?

You can install it by using the following command:

npm install @cadienvan/event-emitter
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How to use it?

Simply import the module and start using it as follows:

import { makeEE } from '@cadienvan/event-emitter';
const myObject = Object.assign({}, makeEE());
function listener(data) {
  console.log(data);
}
myObject.$on('event', listener);
myObject.$emit('event', {});
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Why did I choose to call it makeEE?

I chose to call it makeEE because it is a function which returns an EventEmitter and I didn't want it to conflict with the NodeJS EventEmitter, allowing you to use both in the same project depending on the use case.

How does this work?

The makeEE function returns an object with the following properties:


$on

The $on function takes two arguments: the event name and the listener function.

myObject.$on('event', listener);
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$off

The $off function takes two arguments: the event name and the listener function.

myObject.$off('event', listener);
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$emit

The $emit function takes two arguments: the event name and the data to be passed to the listener function.

myObject.$emit('event', data);
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$once

The $once function takes two arguments: the event name and the listener function.

myObject.$once('event', listener);
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Tests

You can run the tests by using the following command:

npm test
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Scaffolding

This project was generated using Cadienvan's own npm-package-ts-scaffolding so it has all the necessary tools to develop, test and publish a TypeScript package importable both via CommonJS and ES Modules.

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