Javascript check if a decimal is negative

Question

How would i check if a decimal is negative? Because the if statement automatically turns it into a number...

Example:

var x = -0.24324;

how would i parse it so it tells me x is negative/positive?

Thanks

Edit: Maybe i phrased it badly, the variable changes so something it will be positive like 0.00000001, sometimes -0.0003423423, sometimes 0.0000000234

If i put it in a if statement everything is automatically turned into 0 right? And i can't use a parseFloat in the if statement?

Not really sure what you're asking here. Why can't you check `if (x < 0)` ? — Evan Trimboli, Mar 07 '17 at 04:25
Possible duplicate of [Javascript negative number](http://stackoverflow.com/questions/3571717/javascript-negative-number) — kvn, Mar 07 '17 at 04:30

score 0 · Answer 1 · answered Mar 07 '17 at 04:26

0

Just check if x less than zero since it's a number:

if (x < 0) {
  // it's negative
}

answered Mar 07 '17 at 04:26

ide

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score 0 · Answer 2 · answered Mar 07 '17 at 04:30

You can use isNaN() function to check whether it is valid number or not.
If it is, then you can check for positive or negative value.

Something like this:

var x = "-123"
var y = -456;
var z = '-123a';

if(!isNaN(x) && x < 0) {
  console.log(x + ' is negative');
}

if(!isNaN(y) && y < 0) {
  console.log(y + ' is negative');
}

if(!isNaN(z) && z < 0) {
  console.log(z + ' is negative');
}

score 0 · Answer 3 · answered Feb 03 '22 at 11:15

0

const num = -8;

// Old Way

num === 0 ? num : (num > 0 ? 1 : -1); // -1

// ✅ ES6 Way

Math.sign(num); // -1

answered Feb 03 '22 at 11:15

c-2k

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Javascript check if a decimal is negative

3 Answers3