is it safe to use let for a variable which return result? [closed]

Question

I wonder whether it is safe to use let in this scenario:

function test() {
  let result = 0;
  result++;
  return result;
}

Answer 1

Yes, it is perfectly safe and it is the expected way to declare a local variable that you later want to return as the value of the function. Because Javascript is a garbage collected language, the local variable can safely contain any type of value. It can have a simple primitive like you show, or it can even contain an object like this:

function test() {
  let result = {cnt: 0};
  result.cnt++;
  return result;
}

let obj = test();
console.log(obj);     // shows {cnt: 1}

This is safe because though you are returning an object that was declared within the scope of a function and that function scope will go out of scope when the function returns, because Javascript is a garbage-collected language, the object will separately live on in whatever the return value of your function is assigned to outside of the function scope.

Answer 2

To piggy back on the comments posted above.
Const - https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/const is a great way to let yourself as well as other people who are reading your code know that 'this variable wont be reassigned or modified.'

Let - https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/let lets people know that this variable will most likely get reassigned or modified.

Use of let in your case is perfectly okay!