Outside scope this key word in JavaScript?

Question

I am not sure why I'm getting undefined with the code below. I tried to declare a variable under the say method var _this = this and then console.log out _this.name but it did not work.

let dog = {
  name: 'doggo',
  sayName() {
    console.log(this.name)
  }
}
let sayName = dog.sayName
sayName()

You probably want to be using a class: https://codepen.io/anon/pen/MoGLQq — James, Jul 04 '17 at 09:56
Under the assumption that the poster wants multiple dogs with different names — James, Jul 04 '17 at 09:58

score 3 · Answer 1 · answered Jul 04 '17 at 09:53

window.name="test";
sayName();//test

Executes the function in window context so this is window. You may want to keep the dog context either through passing it:

sayName.call(dog);//doggo

Or through keeping a bound function:

let sayName = dog.sayName.bind(dog);
sayName();//doggo

Outside scope this key word in JavaScript?

1 Answers1