What is Math.sign in JavaScript ?

Math.sign

The Math.sign method is used to find the positive or negative state of a number. This method will return:

  • 1 if the number passed is a positive number.
  • -1 if the number passed is a negative number
  • +0 if the number passed is +0
  • -0 if the number passed is -0
  • NaN on all other cases
console.log("Math.sign of 10", Math.sign(10));
console.log("\n---------\nMath.sign of -10", Math.sign(-10));
console.log("\n---------\nMath.sign of 0", Math.sign(0));
console.log("\n---------\nMath.sign of 0", Math.sign(-0));
console.log("\n---------\nMath.sign of undefined", Math.sign());
console.log("\n---------\nMath.sign of null", Math.sign(null));

If the argument passed to the sign function is not a number, then the value will be implicitly converted to a number type.

console.log("---------\nMath.sign of '10'", Math.sign('10'));
console.log("\n---------\nMath.sign of '-10'", Math.sign('-10'));
console.log("\n---------\nMath.sign of 'abc'", Math.sign('abc'));

Using Math.sign

Let’s say we have an array of elements, and we need to print each element and its positive/negative state. Take a look at the code below:

let arr = [1, 2, -3, 0, -4];
for(let i = 0,l = arr.length; i < l; i++){
    if(Math.sign(arr[i]) < 0){
        console.log("Number is ", arr[i], " -> Negative")
    } else {
        console.log("Number is ", arr[i], " -> Positive")
    }
}

Free Resources

License: Creative Commons-Attribution-ShareAlike 4.0 (CC-BY-SA 4.0)