code: function extractRouteArguments(args) {
    let [ lastArg ] = args.splice(-1);
    if (isOption(lastArg)) {
      lastArg = _assign({}, defaultRouteOptions, lastArg);
    } else {
      args.push(lastArg);
      lastArg = defaultRouteOptions;
    }
    let t = 2 - args.length;
    while (t-- > 0) {
      args.push(undefined);
    }
    args.push(lastArg);
    return args;
  }
docs: Extract arguments for a route.
  
  @method extractRouteArguments
  @param {Array} args Of the form [options], [object, code], [function, code]
  [shorthand, options], [shorthand, code, options]
  @return {Array} [handler (i.e. the function, object or shorthand), code,
  options].
  @private