code: function unescape(key) {
    var unescapeRegex = /(=0|=2)/g;
    var unescaperLookup = {
      '=0': '=',
      '=2': ':'
    };
    var keySubstring = key[0] === '.' && key[1] === '$' ? key.substring(2) : key.substring(1);
  
    return ('' + keySubstring).replace(unescapeRegex, function (match) {
      return unescaperLookup[match];
    });
  }
docs: Unescape and unwrap key for human-readable display
  
  @param {string} key to unescape.
  @return {string} the unescaped key.