How to convert null to 0 in Javascript

Question

When pressureSeaLevelRate returns null I need to set it to 0

_currentData['pressureRate'] = data['observation']['pressureSeaLevelRate'];

`_currentData.pressureRate = data?.observation?.pressureSeaLevelRate ?? 0` — Mulan, Dec 29 '22 at 17:14
What's wrong with a simple `if`? `if (... === null) { ... = 0 }` — Andreas, Dec 29 '22 at 17:19
@MichaelM. If any of the already available questions here on SO have the same problem/topic like this one then use one of those to close the question as duplicate of that other question so we don't create yet another copy of an already available information/answer, — Andreas, Dec 29 '22 at 17:58

score 2 · Accepted Answer · answered Dec 29 '22 at 17:15

2

It looks like you want to use the ?? Nullish coalescing operator. Here's an example

const a = null;

const b = a ?? 0;
console.log(b)

const c = 1 + (a ?? 0);
console.log(c);

With your code, you can do this:

_currentData['pressureRate'] = data['observation']['pressureSeaLevelRate'] ?? 0;

or, as Mulan pointed out in the comments, if data or data.pressureSeaLevelRate could also be null, use:

_currentData.pressureRate = data?.observation?.pressureSeaLevelRate ?? 0

answered Dec 29 '22 at 17:15

Michael M.

Nina Scholz · Answer 2 · 2022-12-29T17:23:02.813

1

If you have only numbers and null, you could convert null to a number with unary +.

let value = null;

value = +value;

console.log(value);

edited Dec 29 '22 at 17:23

answered Dec 29 '22 at 17:15

Nina Scholz

score 0 · Answer 3 · answered Dec 29 '22 at 17:14

0

Try this


_currentData['pressureRate'] = Number(data['observation']['pressureSeaLevelRate']);

answered Dec 29 '22 at 17:14

codester_09

3 Answers3