check if on Node Server

gistfile1.txt

(function () {

   // Establish the root object, `window` in the browser, or `global` on the server.
   var root = this;

   // Create a reference to this
   var _ = new Object();

   var isNode = false;

   // Export the Underscore object for **CommonJS**, with backwards-compatibility
   // for the old `require()` API. If we're not in CommonJS, add `_` to the
   // global object.
   if (typeof module !== 'undefined' && module.exports) {
           module.exports = _;
           root.​_ = _​;
           isNode = true;
   } else {
           root.​_ = _​;
   }
})();