Two special functions (arrow function and method)

The arrow function sums up

The arrow function doesn't prototype( Prototype ), So the arrow function itself doesn't have this, To get from context ！

thank ：Js Knowledge about ordinary functions and arrow functions

Method

Binding functions in an object , This function is called the method of this object .

stay JavaScript in , The definition of an object is as follows ：

var xiaoming = {
    
    name: ' Xiao Ming ',
    birth: 1990
};

however , If we give xiaoming Bind a function , You can do more . such as , Write a age() Method , return xiaoming In the age of ：

var xiaoming = {
    
    name: ' Xiao Ming ',
    birth: 1990,
    age: function () {
    
        var y = new Date().getFullYear();
        return y - this.birth;
    }
};

xiaoming.age; // function xiaoming.age()
xiaoming.age();

Functions bound to objects are called methods , It's no different from ordinary functions , But it uses a... Internally this keyword , What is this thing ？

Inside a method ,this It's a special variable , It always points to the current object , That is to say xiaoming This variable . therefore ,this.birth Can get xiaoming Of birth attribute .

This picture is in 01 to encounter vue There has been ！