When running JavaScript labs, you may get an error when you run learn  that says something along the lines of 'undefined method this '. This means that JavaScript did not return any information to the ruby gem about the test. 

First, ensure that the JavaScript tests are running properly with npm test . If they're not, trouble shoot the error you receive from JavaScript.

If the JavaScript tests are running, try running: gem update learn-co  and gem update --system  to fix the error. Test by running learn  again. 

Did this answer your question?