Event Emitter

evem.js

// Minimal Event Handler
// Call makeEmitter(obj) to make obj an event emitter.
// obj.on(event, handler)
// obj.off(event[, handler])
// obj.fire(event[, args...])
// https://gist.github.com/moqmar/1a33e871e9a4b855443d57d40f56d052 (Public Domain/CC0)
function makeEmitter(obj) {
    obj.__l = {}; // Listeners - this.on("update", fn) -> { update: [fn] }
    obj.on = function(ev, fn) {
        if (!this.__l[ev]) this.__l[ev] = [fn];
        else this.__l[ev].push(fn);
    }.bind(obj);
    obj.off = function(ev, fn) {
        if (!this.__l[ev]) return;
        if (!fn) return delete this.__l[ev];
        var i; while ((i = this.__l[ev].indexOf(fn)) > -1) this.__l[ev].splice(i, 1);
        if (!this.__l[ev].length) delete this.__l[ev];
    }.bind(obj);
    obj.fire = function(ev) {
        if (!this.__l[ev]) return;
        var args = Array.prototype.slice.call(arguments, 1);
        for (var i = 0; i < this.__l[ev].length; i++) this.__l[ev][i].apply(this, args);
    }.bind(obj)
}

evem.min.js

function makeEmitter(i){i.__l={},i.on=function(i,t){this.__l[i]?this.__l[i].push(t):this.__l[i]=[t]}.bind(i),i.off=function(i,t){if(this.__l[i]){if(!t)return delete this.__l[i];for(var _;(_=this.__l[i].indexOf(t))>-1;)this.__l[i].splice(_,1);this.__l[i].length||delete this.__l[i]}}.bind(i),i.fire=function(i){if(this.__l[i])for(var t=Array.prototype.slice.call(arguments,1),_=0;_<this.__l[i].length;_++)this.__l[i][_].apply(this,t)}.bind(i)}