Math.sign()

The Math.sign() function returns either a positive or negative +/- 1, indicating the sign of a number passed into the argument. If the number passed into Math.sign() is 0, it will return a +/- 0. Note that if the number is positive, an explicit (+) will not be returned.

Math.sign(x)

x

A number. If this argument is not a number, it is implicitly converted to one.

A number representing the sign of the given argument:

• If the argument is positive, returns 1.
• If the argument is negative, returns -1.
• If the argument is positive zero, returns 0.
• If the argument is negative zero, returns -0.
• Otherwise, NaN is returned.

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).

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

• A polyfill
• Math.abs()
• Math.ceil()
• Math.floor()
• Math.round()
• Math.trunc()