<0.3KB EventEmitter

EventEmitter.js

"use strict";function EventEmitter(){var c=[];return{on:function(d,f){c.push({a:d,b:f})},emit:function(d){c.filter(function(f){return f.a==d}).forEach(function(f){return f.b()})},off:function(d){c.splice(c.indexOf(d),1)}}}

You can save a lot of bytes when using arrow functions. As the cache (c=[]) is inside a block scope, you should use let and arrow functions for all public methods.

I created a fork to show it: https://gist.github.com/cookiengineer/2c922967803e016c36b373d7fc0be634

"use strict";function EventEmitter() {let c=[];return {on:(a,b)=>c.push({a,b}),emit:d=>c.filter(f=>f.a==d).forEach(f=>f.b()),off:d=>c.splice(c.indexOf(d),1)}};

The final result is 165 Bytes :)

@cookiengineer - arrow functions are ES6.

Oh, so it's supposed to be ES5 only?