The Math.sign()
function returns the sign of a number, indicating whether the number is positive, negative or zero.
Math.sign(x)
x
Because sign()
is a static method of Math
, you always use it as Math.sign()
, rather than as a method of a Math
object you created (Math
is not a constructor).
This function has 5 kinds of return values, 1
, -1
, 0
, -0
, NaN
, which represent "positive number", "negative number", "positive zero", "negative zero" and NaN respectively.
The argument passed to this function will be converted to x
type implicitly.
Math.sign()
Math.sign(3); // 1 Math.sign(-3); // -1 Math.sign('-3'); // -1 Math.sign(0); // 0 Math.sign(-0); // -0 Math.sign(NaN); // NaN Math.sign('foo'); // NaN Math.sign(); // NaN
Math.sign = Math.sign || function(x) { x = +x; // convert to a number if (x === 0 || isNaN(x)) { return x; } return x > 0 ? 1 : -1; }
Created by Mozilla Contributors, license: CC-BY-SA 2.5