Installation

Eventverse can be used as a Node module or as an ES6 module.

To install Eventverse through npm, simply use the following command:

$ npm install --save eventverse

Usage

To use Eventverse in a Node project, simply require it like so:

const Eventverse = require('eventverse');

and to use it in the browser, simply import it like so:

// Webpack
import Eventverse from 'eventverse';

// Browser
import Eventverse from './node_modules/eventverse/eventverse.js';

Initialization

After installing and importing Eventverse a new instance can be initialized like so:

const person = new Eventverse();

There is also an initialization option that can be passed to a new instance of Eventverse which allows you to specify the maximum amount of listeners that can be attached to an event. If no value is specified, then 10 is used by default.

| param | type | description | default | |------------------|--------|------------------------------------------------------------------|---------| | maxListenerCount | number | The maximum amount of listeners that can be attached to an event | 10 |

Properties

maxListenerCount

A get method that returns the max amount of listeners allowed for each individual event.

return numMaxListeners = person.maxListenerCount; // returns 10

API

on

Adds a listener function for the given event. If the event doesn't exist, it will be created.

| param | type | description | default | |---------|----------|--------------------------------------------------------------------------------------------|------------| | event | string | The name of the event to add a listener to | | | fn | Function | The function to call when the event is emitted | | | uses | number | Indicates how many times this listener can be called before being destoryed automatically. | Infinity |

Add a function with no parameters:

const helloWorld = () => console.log('Hello World!');

person.on('hello', helloWorld);

Adding a function with parameters:

const helloOtherPerson = (personName) => console.log(`Hello ${personName}!`);

person.on('hello', helloOtherPerson);

Adding a function that only has 2 uses:

const helloWorld = () => console.log('Hello World!');

person.on('hello', helloWorld, 2);

once

Once is the same as on except that it sets a listener that will only be called once and then removed automatically afterwards.

| param | type | description | default | |---------|----------|------------------------------------------------|------------| | event | string | The name of the event to add a listener to | | | fn | Function | The function to call when the event is emitted | |

Add a function with no parameters.

const bonjourWorld = () => console.log('Bonjour World!');

person.once('hello', bonjourWorld);

listenerCount

Returns the number of listeners for a given event.

| param | type | description | default | |-------|--------|----------------------------------------------------------|---------| | event | string | The name of the event to get the number of listeners for | |

return person.listenerCount('hello'); // returns 3

timesCalled

Returns the number of times a listener has been called.

| param | type | description | default | |-------|--------|---------------------------------------------------------------------|---------| | event | string | The name of the event to get the number of times it has been called | |

return person.timesCalled('hello');

emit

Calls all of the listeners attached to the Eventverse instance with the event name and the supplied arguments.

| param | type | description | default | |---------|--------|------------------------------------------------|---------| | event | string | The name of the event to emit | | | ...args | ...* | The arguments to pass to the event's listeners | |

Emitting the hello event with no arguments:

person.emit('hello');

Emitting the hello event with arguments:

person.emit('hello', 'John', 25, 'United States');

removeListener

Removes a listener function from the given event.

| param | type | description | default | |----------|----------|-------------------------------------------------|---------| | event | string | The name of the event to remove a listener from | | | listener | Function | The listener function to remove from the event | |

const helloWorld = () => console.log('Hello World!');

person.removeListener('hello', helloWorld);

removeAllListeners

Removes all listeners from a given event.

| param | type | description | default | |----------|----------|---------------------------------------------------|---------| | event | string | The name of the event to remove all listener from | |

person.removeAllListeners('hello');

Tests

To run all of the available tests, use:

$ npm run test

License

MIT