javascript 面向对象编程设计模式之访问者模式

function Input(inputDom) {
  this.visitiors = {
    'click': [],
    'change': [],
    'special': []
  };
  this.inputDom = inputDom
}

Input.prototype.on = function (eventType, callback) {
  if (typeof this.visitiors[eventType] !== 'undefined') {
    this.visitiors[eventType].push(callback)
  }
};

Input.prototype.off = function (eventType,callback) {
  var visitors = this.visitiors[eventType];
  if(typeof visitors !== 'undefined'){
    var index = visitors.indexOf(callback);
    if(index > 0){
      visitors.splice(index,1)
    }
  }
};

Input.prototype.trigger = function (eventType,event) {
  var visitor = this.visitiors[eventType];
  var eventFormat = processEvent(event);
  if(typeof visitor !== 'undefined'){
    for(var i = 0;i<visitor.length;i++){
      visitor[i](eventFormat)
    }
  }
}

let a = new Input(this.p)
console.log(a)
a.on('click',function () {
  console.log(333)
});
a.trigger('click')