http://www.freecodecamp.com/tylerl-uxai 's solution for Bonfire: Search and Replace

bonfire-search-and-replace.js

// Bonfire: Search and Replace
// Author: @tylerl-uxai
// Challenge: http://www.freecodecamp.com/challenges/bonfire-search-and-replace
// Learn to Code at Free Code Camp (www.freecodecamp.com)
// Rewritten by myself with the help of https://github.com/FreeCodeCamp/FreeCodeCamp/wiki/Bonfire-Search-and-Replace

function myReplace(str, before, after) {
  var i = str.indexOf(before);
  
  if (str[i] == str[i].toUpperCase()){
    after = after.charAt(0).toUpperCase() + after.slice(1);
  }
  return str.replace(before, after);
}

myReplace("A quick brown fox jumped over the lazy dog", "jumped", "leaped");