Difference between 'this' and normal variable declaration

Question

What is the difference between declaring a variable with this in my function than declaring normally using let or var?

const controller = (function() {
  this.name = 'John';
})();

const controller2 = (function() {
  let name = 'Mary';
})();

`this` belongs to objects, it doesn't declare any variables. Also, the provided examples don't make sense, both controller variables are assigned with `undefined`. — Teemu, Jun 21 '18 at 09:12
[This will help you about let and this](https://stackoverflow.com/questions/762011/whats-the-difference-between-using-let-and-var-to-declare-a-variable-in-jav) — tklanilkumar, Jun 21 '18 at 09:15

score 3 · Accepted Answer · answered Jun 21 '18 at 09:15

3

this inside your function is window object. So you are not creating a variable, you are adding a property to the window object

console.log((function(){return this})() === window)

answered Jun 21 '18 at 09:15

Francesco

Assuming strict mode (which you should), it's `undefined` not the global object. – Bergi Jun 21 '18 at 09:29
Right! In such case you get a `TypeError` so it doesn't really makes sense to do that in strict mode – Francesco Jun 21 '18 at 09:34

1 Answers1