How to find difference between two values?

I want return the difference between 2 values how to do that? 0.0.0.1.0 and 0.0.0.1.12

so the difference between these two values is 12 so how to calculate that I tried with Math.abs() but it is fine with single digits.

Solution

Assuming that they are strings (since you can't have more than 1 full stop in a valid JS number), you could split it by . character and calculate the difference of individual components:

function numStringDiff(a, b) {
  // split them on dot characters
  const aParts = a.split('.');
  const bParts = b.split('.');

  // loop using longest array length as a container for mapped results
  return Array(Math.max(aParts.length, bParts.length)).fill(undefined).map((_, i) => {
    const i1 = parseInt(aParts[i] || 0); // fetch aParts[i] or default to 0
    const i2 = parseInt(bParts[i] || 0); // fetch bParts[i] or default to 0

    // return compared value after defaulting the values.
    return i2 - i1;
  });
}

console.log(numStringDiff('0.0.0.1.0', '0.0.0.1.12'));

The problem here is that, as you stated in the comments, they can be of different length. To make it work in this scenario, we must iterate an amount of times equal to the length of the longest array and ensure that any missing items in the shorter one are defaulted to some non-breaking value like 0 so that we can safely subtract every digit present in the longest list with something or 0.

Note that 0 is a value I only used to ensure you can calculate a difference between different-length arrays, choose any (numeric or float) value that fits your needs.

If in this case the second argument has less dots than the first, negative difference will be returned, otherwise if first is longer than last, positive difference will be returned.

Some examples:

numStringDiff('1.1.1', '1.1') // => [0, 0, -1]
numStringDiff('1.1', '1.1.1') // => [0, 0, 1]
numStringDiff('1.1.1', '1.1.1') // => [0, 0, 0]

For the absolute distance between two values, one can simply .map over this array:

numStringDiff('1.1.1', '1.1').map(num => Math.abs(num));
// OR, using short form: 
numStringDiff('1.1.1', '1.1').map(Math.abs);

And finally, should you need the result as a string, simply .join it back together with '.':

numStringDiff('1.1.1', '1.1').map(Math.abs).join('.');

Do know what you are trying to achieve though. If you're trying to manually bisect version numbers (like semver versions) I'd recommend against it since there will always be scenario's uncovered by this function such as pre-releases that wouldn't include only digits but rather 0.0.0-pre-foo-version or something. Since I don't know what it is you're trying to do exactly I'll leave that a responsibility for you to figure out :)