Is func() the same as func?

Question

While learning JavaScript from an "eloquent" book, I stumbled in this program:

function wrapValue(n) {
  let local = n;
  return () => local;
}

let wrap1 = wrapValue(1);
let wrap2 = wrapValue(2);
console.log(wrap1());
// → 1
console.log(wrap2());
// → 2

My problem is the output being wrap1() rather than wrap1.

Is it possible to do even console.log(wrap1)?
And if it's possible, are wrap1() and wrap1 the same thing?

EDIT: they flagged the question as duplicate of What is the difference between a function call and function reference? however my problem was thinking that in let wrap1 = wrapValue(1);, wrap1 gets a value, but the truth is that it gets a function. That's it. The supposed duplicate have nothing to do with my blindness.

Duplicate of [What is the difference between a function call and function reference?](https://stackoverflow.com/questions/15886272/what-is-the-difference-between-a-function-call-and-function-reference) — Guy Incognito, Jan 09 '21 at 00:17
`wrapValue` returns an arrow function `() => ` that's why you need to call it to get result by adding `()` — Kubwimana Adrien, Jan 09 '21 at 00:23
@KubwimanaAdrien oh I didn't see that! So I can't do `console.log(wrap1)` because `wrap1` is not the returned value but the returned function, right? — anotherOne, Jan 09 '21 at 00:28

SuperStormer · Accepted Answer · 2021-01-09T00:25:49.207

1

wrapValue returns a lambda function, which is what console.log(wrap1) will print. console.log(wrap1()) actually runs that function and prints the result.

edited Jan 09 '21 at 00:25

answered Jan 09 '21 at 00:16

SuperStormer

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Thank you for the answer. So if I get it right, the output would be the same but `wrap1()` does an unnecessary further step, isn't it? – anotherOne Jan 09 '21 at 00:24
No, the output is different. The first one prints the function itself, but the second one prints the function's result. – SuperStormer Jan 09 '21 at 00:25
You mean that in the first case the output would be something like: `function wrapValue(n) { let local = n; return () => local; }`? – anotherOne Jan 09 '21 at 00:31
No, just () => local. You can check in chrome devtools – SuperStormer Jan 09 '21 at 00:42

Is func() the same as func?

1 Answers1