The difference between call, apply and bind

1.call()

The first parameter: this points to
if you want to pass parameters, followed by parameters 

function fn(x) {
    console.log(x);    // 打印的是1
    console.log(this.name);    // 打印的是小寿司
}

const obj = {
    name:"小寿司"
}

fn.call(obj,1);    // 此时fn()这个函数this指向obj这个对象，原来fn()这个函数的this指向window
                   // 原来fn()这个函数内部是没有name这个值，
                   // 改变this指向后就可以去obj这个对象中找name

2.apply()

The difference from the first method is that the parameters are represented in the form of an array

function fn(x,y){
   console.log(x,y);    // 打印的是1,2
   console.log(this);    // 打印的是obj这个对象
   console.log(this.name)    // 打印的是小寿司
}
var obj = {
   name:"小寿司"
}
fn(1,2);	//这里执行输出的this是window全局对象，
fn.apply(obj,[1,2]);	//改变this指向后，this.name就是小寿司

After running, the console output is as follows:

 

 

3.bind()

bind only changes the point of this, and does not call the function (both call and apply)

function fn(x,y){
   console.log(x,y);  
   console.log(this.name)
}
const obj = {
   name:"小寿司"
}
fn(1,2);
fn.bind(obj,1,2)();    // 此时若没有后面的小括号，fn()这个函数将不会调用

The difference between call and apply :

The call() method has the same function as the apply() method, the difference is that they receive different parameters.