3.3. The Observer Pattern (ok)

C:\xampp\htdocs\php\js\main.js

require(['observer/init'],function(init) {
	var examples = {
		observer: init
	}
	for (var example in examples) {
		examples[example].init();
	}
});

C:\xampp\htdocs\php\js\observer\init.js

define(function(require) {
  'use strict';
  return {
    init: function() {
      var subject, observer, otherObserver, data, moreData;
      var Subject = require('observer/subject');
      var Observer = require('observer/observer');
      subject = new Subject();
      observer = new Observer('observer1');
      otherObserver = new Observer('observer2');
      data = {
        prop: 'something'
      };
      moreData = {
        prop: 'something else'
      };
      subject.observe(observer);
      subject.observe(otherObserver);
      subject.add(data);
      subject.add(moreData);
      subject.unObserve(observer);
      subject.remove(data);
    }
  };
});

C:\xampp\htdocs\php\js\observer\subject.js

define(function(require) {
  'use strict';
  var Observers = require('observer/observers');
  var Collection = function(items) {
    this.observers = new Observers();
    this.collection = items || [];
  };
  Collection.prototype.observe = function(observer) {
    this.observers.add(observer);
  };
  Collection.prototype.unObserve = function(observer) {
    this.observers.remove(observer);
  };
  Collection.prototype.notify = function(event, data) {
    this.observers.get().forEach(function(observer) {
      observer.notify(event, data);
    });
  };
  Collection.prototype.add = function(item) {
    this.collection.push(item);
    this.notify('added', item);
  };
  Collection.prototype.remove = function(itemToRemove) {
    this.collection = this.collection.filter(function(item) {
      if (item !== itemToRemove) {
        return true;
      }
      this.notify('removed', item);
      return false;
    }, this);
  };
  return Collection;
});

C:\xampp\htdocs\php\js\observer\observers.js

define(function() {
  'use strict';
  var Observers = function() {
    this.observers = [];
  };
  Observers.prototype.add = function(observer) {
    this.observers.push(observer);
  };
  Observers.prototype.remove = function(observerToRemove) {
    this.observers = this.observers.filter(function(observer) {
      return observer !== observerToRemove;
    });
  };
  Observers.prototype.get = function() {
    return this.observers;
  };
  return Observers;
});

C:\xampp\htdocs\php\js\observer\observer.js

define(function() {
  'use strict';
  var Observer = function(name) {
    this.name = name;
  };
  Observer.prototype.notify = function(event, data) {
    console.log('The event was ', '"' + event + '",', 'the data was', data, 'and I am ', this.name);
  };
  return Observer;
});