# Copy sign to number

JavaScript, Math · Oct 7, 2020

Returns the absolute value of the first number, but the sign of the second.

- Use
`Math.sign()`

to check if the two numbers have the same sign. - Return
`x`

if they do,`-x`

otherwise.

`const copySign = (x, y) => Math.sign(x) === Math.sign(y) ? x : -x;`

```
copySign(2, 3); // 2
copySign(2, -3); // -2
copySign(-2, 3); // 2
copySign(-2, -3); // -2
```