Is this an arrow function declaration? Is there such a thing?

Question

I am looking into function expressions vs function declarations using arrow functions.

I am thinking this is an arrow function expression:

const johan = greeting = () => {
  console.log("Hi from arrow function expression");
};

and that this is an arrow function decleration:

 ludwig = () => {
  console.log("Hi from arrow function declaration");
};

Is that correct? Or maybe there is no such thing as an arrow function declaration? Maybe there is only arrow function expressions?

If so, what is it called when I put a named arrow function expression in another variable?

Happy for any answer! :)

Both are the same thing. `ludwig` just happens to have been defined earlier, with `var` or `let`, or possibly none of them — Emanuel Vintilă, Dec 07 '20 at 14:17
Note that `const johan = greeting = 42` is also valid - it just assigns both variables the same value. — IMSoP, Dec 07 '20 at 14:20
*Or maybe there is no such is as an arrow function declaration* Correct, there's no *arrow function declaration*. Arrow functions are used only in expressions. — Wiktor Zychla, Dec 07 '20 at 14:22

score 2 · Accepted Answer · answered Dec 07 '20 at 14:19

2

No.

There are function declarations, function expressions, and arrow functions (the syntax which creates them also being an expression).

ludwig = () => {
  console.log("Hi from arrow function declaration");
};

This is assigning a value (an arrow function) to a variable.

The variable declaration is missing, so either it appeared earlier or this creates an implicit global (which is forbidden in strict mode).

answered Dec 07 '20 at 14:19

Quentin

Very interesting (regarding the strict mode as well), thanks for the answer and thanks for the links, will read in on them! Thanks to all you answering! – Johan Berglund Dec 08 '20 at 12:40

1 Answers1