Leading Zeros in JavaScript Numbers

In JavaScript, is there a way to automatically add leading zeros to numbers to achieve a specific string length? For instance, converting 5 to "05" with a target length of 2?

Solution:

Conversion to String

Since numbers inherently don't have leading zeros, we need to convert the number to a string first. Here's a sample function:

function pad(num, size) {
  num = num.toString();
  while (num.length 
Example:
pad(5, 2); // "05"
Alternative Approach
If the maximum number of leading zeros is known, an alternative method can be more efficient:
function pad(num, size) {
  var s = "000000000"   num;
  return s.substr(s.length - size);
}
Negative Numbers
Handling negative numbers requires stripping the negative sign and re-adding it after padding:
function padWithSign(num, size) {
  if (num