JavaScript模板方法模式：原理、实现与钩子函数详解

var Beverage = function(){};
Beverage.prototype.boilWater = function(){
  console.log('把水煮沸');
};
Beverage.prototype.pourInCup = function(){
  throw new Error( '子类必须重写pourInCup' );
};
Beverage.prototype.addCondiments = function(){
  throw new Error( '子类必须重写addCondiments方法' );
};
Beverage.prototype.customerWantsConditions = function(){
  return true; //默认需要调料
};
Beverage.prototype.init = function(){
  this.boilWater();
  this.brew();
  this.pourInCup();
  if(this.customerWantsCondiments()){
    //如果挂钩返回true，则需要调料
    this.addCondiments();
  }
};

var CoffeeWithHook = function(){};
CoffeeWithHook.prototype = new Beverage();
CoffeeWithHook.prototype.brew = function(){
  console.log('把咖啡倒进杯子');
};
CoffeeWithHook.prototype.addCondiments = function(){
  console.log('加糖和牛奶');
};
CoffeeWithHook.prototype.customerWantsCondiments = function(){
 return window.confirm( '请问需要调料吗？' );
};

var coffeeWithHook = new CoffeeWithHook();
coffeeWithHook.init();

var Beverage = function( param ){
  var boilWater = function(){
   console.log( '把水煮沸' );
  };
  var brew = param.brew || function(){
   throw new Error( '必须传递brew方法' );
  };
  var pourInCup = param.pourInCup || function(){
    throw new Error( '必须传递pourInCup方法' );
  };
  var addCondiments = param.addCondiments || function(){
   throw new Error( '必须传递addCondiments方法' );
  };
  var F = function(){};
  F.prototype.init = function(){
   boilWater();
   brew();
   pourInCup();
   addCondiments();
  };
  return F;
};
var Coffee = Beverage({
  brew: function(){
     console.log( '用沸水冲泡咖啡' );
  },
  pourInCup: function(){
    console.log('把咖啡倒进杯子');
  },
  addCondiments: function(){
    console.log('加糖和牛奶');
  }
});
var coffee = new Coffee();
coffee.init();