Flip a boolean value in a simple way javascript

Question

Given boolean value completed = false how do I flip it back and forth? I could of course do something like this:

if (completed) {
    completed = false
} else {
    completed = true
}

But that feels hacky and too long. Is there any slick and cleaner way of doing this? Thanks.

score 1 · Accepted Answer · answered Jul 05 '21 at 21:21

1

Assuming you declared variable with let or var, so that you can reassign the value :

completed = !completed

answered Jul 05 '21 at 21:21

spurushottam13

What does `let` or `var` have to do with it? – Ivar Jul 05 '21 at 21:25
Could be a function argument also – charlietfl Jul 05 '21 at 21:27
@Ivar if you don't use `let` or `var` and use `const` then you are not allowed to reassign the variable. – spurushottam13 Jan 17 '22 at 11:52
I see what you mean now. That might be worth to mention explicitly. You can also not declare your variable at all (it becoming an implicit global variable), in which case `completed = !completed` will still work without any issue. (Hence my previous question.) – Ivar Jan 17 '22 at 12:34

1 Answers1