js中call、apply、bind的區別

var Person = {
  name : `alice`,
  say : function(txt1,txt2) {
    console.info(txt1+txt2);
    console.info(this.name);
  }
}

var Dog = {
  name : `tom`,
  say : function(txt1,txt2) {
    console.info(txt1+txt2);
    console.info(this.name);
  }
}
var arr = [`hello`,`hi`];
Person.say(`hello`,`hi`);
Dog.say(`wang~`,`wang2~`);
Person.say.call(Dog,`hello`,`hi`);//Person.say內部的this指向了Dog，多個引數用逗號隔開
Person.say.apply(Dog,arr);//第二個引數是陣列，引數數量可以是未知的
var PersonSay = Person.say.bind(Dog,`hello`,`hi`);//不會立即執行，觸發返回函式才會執行
PersonSay();



>>>hellohi
>>>alice
>>>wang~wang2~
>>>tom
>>>hellohi
>>>tom
>>>hellohi
>>>tom
>>>hellohi
>>>tom