如何在对象中调用方法

Question

I am having trouble calling the object method,it always throw a error this.b is not a function

var a={
   b:()=>"3333",
   c:()=>this.b();
}
console.log(a.c());

Answer 1

Simplest way to make your code working is to use a instead of this

var a = {
   b: () => "3333",
   c: () => a.b()
};

console.log(a.c());

Answer 2

Your code does not work because the arrow function binds the function to the scope in which it is defined. In this case, you are in the global scope when you create the function "c" using the arrow function. Often this can be fixed with a bind call. However, in this case, I would just convert to a classical function. This is a good lesson in why you should not be lazy and use the arrow function to save a few characters. The arrow function IS NOT the same as a normal function and can lead to hard to debug bugs.

 var a={ b:()=>"3333", c:function () { return this.b() } } console.log(ac()) 

Answer 3

Basically, the reference of c, will call the value based on lexical scope, the same of ' window.c() '.

To fix your implementation, do:

var a={
   b:()=>{ return "333"; },
   c:function(){ return this.b(); }
}
console.log(a.c()); // Here we have a "333"

Why this happens?

The function expressions work about dynamic scope, different of Arrow Functions. To access Object Properties and reference to same this, use { yourProperty: function() { return "Hello, World"; } } { yourProperty: function() { return "Hello, World"; } }