Search code examples
javascriptzero

Javascript - Identifying Positive 0 and negative 0 numbers

I have a requirement where i have to identify if the number is a positive 0 or a negative 0 and do color coding for those numbers. This is applicable only for 0s and not greater or lesser than 0.

i.e.:

  1. 0.00000983 (Positive Zero)

  2. -0.0000343 (Negative Zero)

I tried below method but this does not help for values having decimals with 0. Please guide.

function isMinusZero(value) {
  return 1/value === -Infinity;
}

isMinusZero(0); // false
isMinusZero(-0); // true
Solution

  • Here is an alternative:

    function isMinusZero(value) {
  if (Object.is(value, -0)) return true;   // handles OP's specific requirement
  if (value === 0) return false;
  return 1/Math.abs(Math.ceil(value)) === Infinity;
}

console.log(isMinusZero(1234)); // false
console.log(isMinusZero(-1223)); // false
console.log(isMinusZero(0)); // false
console.log(isMinusZero(-0)); // true
console.log(isMinusZero(0.0000000000000000000000000000000000000000976767)); // false
console.log(isMinusZero(-0.0000000000000000000000000000000000000000967676767)); // true
console.log(isMinusZero(-0.0000000000003400003400000000000000034000000000967676767)); // true

    References: