Usage of call(), apply()

1, call() and apply() are used to change this points to, the difference is that the parameter list is different(The former is a continuous parameter, the latter is a parameter array)

2, method definition:

      function.apply(thisObj[, argArray])
        function.call(thisObj[, arg1[, arg2[, [,...argN]]]]);

Specially, when no parameters are passed, function.call() is quite To execute this function

3, example:

Because apply() and # The ##call() methods have the same effect, so here we take call() as an example, apply() Similarly:

 //定义一个Car的构造函数
      function Car(name,height){
            this.name=name;
             this.height=height;
         }

     function Maserati(name,age,height,width){
           this.name=name;
           this.age=age;
           this.height=height;
           this.width=width;
      }
  可以发现这里函数2包含了函数1的所有属性，即是继承的意思
       因此函数2这里可以用call()方法改写成
      function Maserati(name,age,height,width){
           Car.call(this,name,age);//此处this就是指向Maserati，此时Maserati就拥有Car的所有属性和方法了。
          this.height=height;
         this.width=width;
       }
   var a=new Maserati("maserati",23,188,98);

The following results are obtained:

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