Get the absolute value of a number in Javascript

Here is a fast way to obtain the absolute value of a number. It's applicable on every language:

x = -25;
console.log((x ^ (x >> 31)) - (x >> 31));

You mean like getting the absolute value of a number? The Math.abs javascript function is designed exactly for this purpose.

var x = -25;
x = Math.abs(x); // x would now be 25 
console.log(x);

Here are some test cases from the documentation:

Math.abs('-1');     // 1
Math.abs(-2);       // 2
Math.abs(null);     // 0
Math.abs("string"); // NaN
Math.abs();         // NaN

If you want to see how JavaScript implements this feature under the hood you can check out this post.

Blog Post

Here is the implementation based on the chromium source code.

function MathAbs(x) {
  x = +x;
  return (x > 0) ? x : 0 - x;
}

console.log(MathAbs(-25));

I think you are looking for Math.abs(x)

https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Math/abs