Why does this points to an empty object in the following js code?

Question

I have thought this would points to the object person but it actually points to an empty object. Can anyone explain?

var person = {
    name: 'James',
    birthYear: '1991',
    getAge: () => new Date().getFullYear() - this.birthYear // this points to an empty object here. test in nodejs.
}

Possible duplicate of [Arrow function vs function declaration / expressions: Are they equivalent / exchangeable?](http://stackoverflow.com/questions/34361379/arrow-function-vs-function-declaration-expressions-are-they-equivalent-exch) — 4castle, May 06 '17 at 17:15
Arrow functions don't bind `this` in the same way as normal functions. See the duplicate. — 4castle, May 06 '17 at 17:18

score 0 · Accepted Answer · answered May 06 '17 at 17:20

if you use arrow functions you are refering to the global 'this'.

this:

getAge: () => new Date().getFullYear() - this.birthYear

is different from this:

getAge: function() {
          new Date().getFullYear() - this.birthYear
        }

have a look here: https://developer.mozilla.org/it/docs/Web/JavaScript/Reference/Functions_and_function_scope/Arrow_functions

Why does this points to an empty object in the following js code?

1 Answers1