How can I determine what line is causing a 404 error?

Question

I have a terrible repeating error of 404 not found for a GET request.

The call looks like this in the JavaScript console

GET some_path/undefined 404 ( No         


        

Answer 1

On chrome you can add breakpoints on XHR and then you should see the callstack. Go to developer tools -> "sources" tab -> "XHR Breakpoints" and add a breakpoint filtered by the relevant URL