Operator to test for falsy values with zero treated as truthy

Question

Is there a minimalistic syntax to do the same as x === 0 ? true : !!x. The goal of this expression is to avoid the exclusion of zero as falsy and yet make sure other falsy values do are converted to false.

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Nullish_coalescing_operator — Teemu, Aug 30 '21 at 08:48
@JayCodist: yes, just zero. @Teemu: I fail to see how `??` helps — Akheloes, Aug 30 '21 at 08:52
You want to allow *any truthy value* and `0`? Including objects, arrays, strings etc? — deceze, Aug 30 '21 at 09:01
@deceze: I want to test a condition where `null` and `undefined` should return a falsy but a zero-value should pass. — Akheloes, Aug 30 '21 at 09:04
@SalmanA: In short I am correcting a bug, the current code is working I just was curious if it could be made shorter or more efficient since it seemed like the type of expression that could be managed by some peculiar operator. — Akheloes, Aug 30 '21 at 09:05
So, would `typeof x === 'number'` be an option, or is that too restrictive…? — deceze, Aug 30 '21 at 09:15
@deceze: this could actually make for a smart refactoring, it does answer the specs and is clean enough ! — Akheloes, Aug 30 '21 at 10:20
Ternary operators are already designed to be excessively succinct as to be practically unreadable... you want something *even shorter*? — TylerH, Aug 30 '21 at 14:28
@TylerH: that a good point, I'll leave it at the current "shortiness", should be fine. — Akheloes, Aug 30 '21 at 14:32

score 3 · Accepted Answer · answered Aug 30 '21 at 08:59

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Basically, you want to allow any number?

typeof x === 'number'

answered Aug 30 '21 at 08:59

deceze

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He might want to treat NaN as falsy as well which needs an extra `&&`. – Salman A Aug 30 '21 at 12:47
https://stackoverflow.com/questions/68981254/operator-to-account-for-zero-but-not-undefined-null/68981425?noredirect=1#comment121915138_68981254… – deceze Aug 30 '21 at 12:48
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FWIW, this solution is technically one character longer than OP's current solution. – TylerH Aug 30 '21 at 14:34
This doesn't really do it. The OP wants to test for boolean, with all numbers considered truthy. And this will evaluate to false, if x is a truthy value in another type – JayCodist Aug 31 '21 at 08:49

score 2 · Answer 2 · answered Aug 30 '21 at 08:58

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The most minimalist syntax I can think of is

x === 0 || Boolean(x)

answered Aug 30 '21 at 08:58

JayCodist

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Ashley · Answer 3 · 2021-08-30T15:54:24.250

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I'm not sure that there's a better solution than what you've got. You could also use !!x || x === 0 though

edited Aug 30 '21 at 15:54

answered Aug 30 '21 at 09:01

Ashley

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That would not always return a boolean – trincot Aug 30 '21 at 09:02
That is true, yeah. I'll amend my answer but there is already a better answer above. – Ashley Aug 30 '21 at 15:54

Operator to test for falsy values with zero treated as truthy

3 Answers3