mu-emitter exercise

executor.js

define([ "./config", "when/when" ], function (config, when) {
  "use strict";

  var UNDEFINED;
  var CALLBACK = config.callback;
  var SCOPE = config.scope;
  var HEAD = config.head;
  var NEXT = config.next;


  return function executor(event, handlers, args) {

    var _handlers = [];
    var _handlersCount = 0;
    var _callback = event[CALLBACK];
    var _scope = event[SCOPE];
    var handler;

    for (handler = handlers[HEAD]; handler !== UNDEFINED; handler = handler[NEXT]) {
      if (_callback && handler[CALLBACK] !== _callback) {
        continue;
      }

      if (_scope && handler[SCOPE] !== _scope) {
        continue;
      }

      _handlers[_handlersCount++] = handler;
    }

    //return _handlers.reduce(function (previous, _handler) {
    return when.reduce(_handlers, function (previous, _handler) {
      return _handler.handle(previous);
    }, args);
  };
});

index.js

require({
  "baseUrl": "bower_components",

  "deps": [ "mu-emitter/main", "../executor", "when/when" ],

  "callback": function (Emitter, Executor, when) {

    var emitter1 = new Emitter();

    emitter1.on('x', f1);
    emitter1.one('x', f1);
    //emitter1.on('x', f1);
    //emitter1.on('x', f2); 
    //emitter1.on('x', f3);
    //emitter1.on('x', f4); 

    function f1(value){
      console.log(value);
      return [value + 1];
    }

    function f2(value){
      console.log(value);
      return [value + 1];
    }

    function f3(value){
      console.log(value);
      return [value + 1];
    }

    function f4(value){
      console.log(value);
      return [value + 1];
    }

    var res = emitter1.emit({
      type: 'x',
      executor: Executor
    }, 1);
    var res2 = emitter1.emit({
      type: 'x',
      executor: Executor
    }, 1);
    res.then(function(value){
      console.log(value);
    });

    function callback(){
      console.log('call me', this);
      return when.resolve('x').delay(1000).then(function(){
        console.log('bump');
      });
    }
  }
});