1) Open the Chrome developer tools (Ctrl+Shift+I)
2) Enable the option "Pause on exceptions" by clicking the round icon that contains a Pause sign.
3) Check the option "Pause on Caught Exceptions"
4) Reload the page
5) When the exception occurs, look at the live "Call Stack", as show in the following screenshot:
You can then double-click on any element of the Call Stack, and it will show you the corresponding source code. You can then inspect the value of the variables by placing the mouse pointer over them.