I'm new to javascript and cannot understand simple thing - what is the difference between
(x) => { return x*2}
and
x => { return x*2} //(just for example, may not work)
Can someone explain or give link for description?
I'm new to javascript and cannot understand simple thing - what is the difference between
(x) => { return x*2}
and
x => { return x*2} //(just for example, may not work)
Can someone explain or give link for description?
Share Improve this question edited Feb 18, 2022 at 19:18 VLAZ 29.1k9 gold badges63 silver badges84 bronze badges asked May 9, 2017 at 18:45 DmitryDmitry 5812 gold badges8 silver badges20 bronze badges 3-
1
The parenthesis around
xonly are required when there are two or more input arguments. With just one (as you've shown here), the two statements are identical. – Scott Marcus Commented May 9, 2017 at 18:46 -
One has parens around a single argument, one doesn't; either is legal. developer.mozilla/en-US/docs/Web/JavaScript/Reference/… Note that using
...here is potentially misleading depending on what they represent. They're a thing in ES6: developer.mozilla/en-US/docs/Web/JavaScript/Reference/… – Dave Newton Commented May 9, 2017 at 18:46 - 1 See also stackoverflow./questions/41085189/… for some points on optional parentheses. – Estus Flask Commented May 9, 2017 at 19:22
1 Answer
Reset to default 11The parenthesis around input arguments (x in this case) are only required when there are two or more input arguments. With just one (as you've shown here), the two statements are identical.
(x) => { return x * 2; } is the same as x => { return x * 2; }
But,
(x, y) => { return x * y; }
Requires parenthesis around the input arguments.
See this for all the gory details!