写出 构造函数模式、混合模式、模块模式、工厂模式、单例模式、发布订阅模式的范例。

• 构造函数模式

  var Person = function(name, age) {
    this.name = name;
    this.age = age;
  }
  Person.prototype.sayName = function() {
    return this.name;
  }
  var student = new Person("htkz", 30);
  console.log(student)
  

• 混合模式

  var Person = function(name, age) {
    this.name = name;
    this.age = age;
  };
  Person.prototype.sayName = function() {
    console.log(this.name);
  }
  
  var Student = function(name, age, score) {
    Person.call(this, name, age);
    this.score = score;
  }
  Student.prototype = Object.create(Person.prototype);
  
  Student.prototype.sayScore = function() {
    console.log(this.score);
  }
  var student = new Student("htkz", 28, 99);
  console.log(student)
  

• 模块模式

  var Person = (function(){
    var name = "htkz";
    function sayName() {
      console.log(name);
    }
    return {
      name: name,
      sayName: sayName
    }
  })()
  

• 工厂模式

  function createPerson(opts) {
    var person = {
      name: opts.name || 'htkz'
    }
    person.sayName = function() {
      console.log(this.name);
    }
    return person;
  }
  var p1 = createPerson({name: 'htkz'});
  var p2 = createPerson({name: '1234'});
  

• 单例模式

  var People = (function() {
    var instance;
    function init(name) {
      return name;
    }
    return {
      createPeople: function(name) {
        if(!instance) {
          instance = init(name);
        }
        return instance;
      }
    }
  })();
  var obj1 = People.createPeople('ts123');
  var obj2 = People.createPeople('456');
  

• 发布订阅模式

  var EventCenter = (function() {
    var events = {};
    function on (evt, handler) {
      events[evt] = events[evt] || [];
      events[evt].push({
        handler: handler
      });
    }
    
    function fire(evt, args) {
      if(!events[evt]) {
        return;
      }
      for(var i = 0; i < events[evt].length; i++) {
        events[evt][i].handler(args);
      }
    }
    
    return {
      on: on,
      fire: fire
    }
  })();
  EventCenter.on('hit', function() {
    console.log('hit');
  })
  EventCenter.fire('hit');
  

  ​

使用发布订阅模式写一个事件管理器，可以实现如下方式调用

Event.on('change', function(val){
    console.log('change...  now val is ' + val);  
});
Event.fire('change', '饥人谷');
Event.off('changer');

var Event = (function() {
  var events = {};
  function on (evt, handler) {
    events[evt] = events[evt] || [];
    events[evt].push({
      handler: handler
    });
  }
  
  function fire(evt, args) {
    if(!events[evt]) {
      return;
    }
    for(var i = 0; i < events[evt].length; i++) {
      events[evt][i].handler(args);
    }
  }
  
  function off(evt) {
    delete events[evt];
  }
  
  function test() {
    console.log(events);
  }
  
  return {
    on: on,
    fire: fire,
    off: off,
    test: test
  }
})();

Event.on('change', function(val){
    console.log('change...  now val is ' + val);  
});
Event.fire('change', '饥人谷');
Event.off('change');
Event.fire('change', '饥人谷');

​