code: function replaceWord(replaceMap, keepMap, rules) {
          return function (word) {
              // Get the correct token and case restoration functions.
              var token = word.toLowerCase();
              // Check against the keep object map.
              if (keepMap.hasOwnProperty(token)) {
                  return restoreCase(word, token);
              }
              // Check against the replacement map for a direct word replacement.
              if (replaceMap.hasOwnProperty(token)) {
                  return restoreCase(word, replaceMap[token]);
              }
              // Run all the rules against the word.
              return sanitizeWord(token, word, rules);
          };
      }
docs: Replace a word with the updated word.
  
  @param  {Object}   replaceMap
  @param  {Object}   keepMap
  @param  {Array}    rules
  @return {Function}