ui/node_modules/layout-base/src/util/Emitter.js

function Emitter(){
  this.listeners = [];
}

var p = Emitter.prototype;

p.addListener = function( event, callback ){
  this.listeners.push({
    event: event,
    callback: callback
  });
};

p.removeListener = function( event, callback ){
  for( var i = this.listeners.length; i >= 0; i-- ){
    var l = this.listeners[i];

    if( l.event === event && l.callback === callback ){
      this.listeners.splice( i, 1 );
    }
  }
};

p.emit = function( event, data ){
  for( var i = 0; i < this.listeners.length; i++ ){
    var l = this.listeners[i];

    if( event === l.event ){
      l.callback( data );
    }
  }
};

module.exports = Emitter;