docs: function watch() {
      for (var _len = arguments.length, args = Array(_len), _key = 0; _key < _len; _key++) {
        args[_key] = arguments[_key];
      }
  
      var path = args[0];
      var handler = args[1];
  
      if (args.length < 2) {
  
        // Run
        if (args.length === 0) return watch.run();
  
        switch (typeof path) {
          case 'object':
            for (var _path in path) {
              watch(_path, path[_path]);
            }
            break;
  
          case 'string':
            watch.run({ url: path });
            break;
  
          default:
            throw new Error('Illage usage.');
        }
  
        return watch;
      } else {
        if (!('_watching' in watch)) {
          watch._watching = [];
        }
  
        var rule = createRule(path, handler);
        watch._watching.push(rule);
      }
  
      return watch;
    }