Get The Absolute Value Of A Number In Javascript

I want to get the absolute value of a number in JavaScript. That is, drop the sign. I know mathematically I can do this by squaring the number then taking the square root, but I al

Solution 1:

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

Solution 2:

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));

Solution 3:

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.

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

console.log(MathAbs(-25));

Solution 4:

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

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

Solution 5:

Alternative solution

Math.max(x,-x)

letabs = x => Math.max(x,-x);

console.log( abs(24), abs(-24) );

Also the Rick answer can be shorted to x>0 ? x : -x