javascript selector not requiring jQuery

vanilla-selector.js

var S = function (selector, context) {
    if (typeof selector === 'string') {
      if (context) {
        var cont;
        if (context.jquery) {
          cont = context[0];
          if (!cont) return context;
        } else {
          cont = context;
        }
        return $(cont.querySelectorAll(selector));
      }

      return $(document.querySelectorAll(selector));
    }

    return $(selector, context);
  };