http://www.freecodecamp.com/minsooshin 's solution for Bonfire: Search and Replace

bonfire-search-and-replace.js

// Bonfire: Search and Replace
// Author: @minsooshin
// Challenge: http://www.freecodecamp.com/challenges/bonfire-search-and-replace
// Learn to Code at Free Code Camp (www.freecodecamp.com)

function myReplace(str, before, after) {
  if ((/^[A-Z]/).test(before)) after = after.charAt(0).toUpperCase() + after.slice(1);
  str = str.replace(new RegExp(before, 'gi'), after);
  return str;
}

myReplace("He is Sleeping on the couch", "Sleeping", "sitting");