Compare two strings really carefully to work out what's different

longCompare.js

function longCompare(actual, expected) {
  function format(str) {
    if (typeof str === 'string') {
      return JSON.stringify(str).replace(/^\"/g, '\'').replace(/\"$/g, '\'');
    } else {
      return str;
    }
  }
  for (var i = 0; i < actual.length || i < expected.length; i++) {
    if (actual.charAt(i) !== expected.charAt(i)) {
      console.log(format(actual.charAt(i)) + '!=' + format(expected.charAt(i)));
    } else {
      console.log(format(actual.charAt(i)) + '=' + format(expected.charAt(i)));
    }
  };
}