bind,apply,call的区别

 

在Javascript中，bind, apply, call方法都可以显式绑定上下文this，这三者有何不同呢？


bind只绑定this不马上执行

 

var person = {
    firstname: 'darren',
    lastname: 'ji',
    getFullName: function(){
        var fullname = this.firstname + ' ' + this.lastname;
        return fullname;
    }
};

//在浏览器中这里的this就是指向window
var logName = function(arg1, arg2){
    console.log(this.getFullName());
}

//bind只是设置了this的指向，本身并不能执行
var logPersonName = logName.bind(person);

//darren ji
logPersonName();

 

call不仅绑定this，还马上执行，并接受可变参数

 

var person = {
    firstname: 'darren',
    lastname: 'ji',
    getFullName: function(){
        var fullname = this.firstname + ' ' + this.lastname;
        return fullname;
    }
};

//在浏览器中这里的this就是指向window
var logName = function(arg1, arg2){
    console.log(this.getFullName());
    console.log('Arguments: ' + arg1 + ' ' + arg2);
}

//darren ji
//Arguments: en es
logName.call(person, 'en','es');

 

apply不仅绑定this,也马上执行，并接受数组

 

var person = {
    firstname: 'darren',
    lastname: 'ji',
    getFullName: function(){
        var fullname = this.firstname + ' ' + this.lastname;
        return fullname;
    }
};

//在浏览器中这里的this就是指向window
var logName = function(arg1, arg2){
    console.log(this.getFullName());
    console.log('Arguments: ' + arg1 + ' ' + arg2);
}

//darren ji
//Arguments: en es
logName.apply(person, ['en', 'es']);