How to format numbers similar to Stack Overflow reputation format

Question

I want to convert a number into a string representation with a format similar to Stack Overflow reputation display.

e.g.

• 999 == \'999\'
• 1000 =

Answer 1

Another approach that produces exactly the desired output:

function getRepString (rep) {
  rep = rep+''; // coerce to string
  if (rep < 1000) {
    return rep; // return the same number
  }
  if (rep < 10000) { // place a comma between
    return rep.charAt(0) + ',' + rep.substring(1);
  }
  // divide and format
  return (rep/1000).toFixed(rep % 1000 != 0)+'k';
}

Check the output results here.