This JS error has been driving me nuts in the app I am trying to write.
For testing I stripped down the code to the minimum runnable example, but still the same JS Error "TypeError: 'undefined' is not an object".
(Actually my "real" app continues to run after that initial error, but some more strange JS errors occur, so I thought it wise to start the investigation with the first JS error.)
Is there any debugging trick I could learn?
I have been trying to find the cause myself, but was completely at a loss: There was no context info in the mobile "console". When I installed a global window.onerror handler and tried to get a stacktrace - there just wasn't one. No bug on the desktop version, so I couldn't use the developer tools of those browsers.
So, how do you found it so quickly?
Weinre is a nice tool, although for this one using an iPad was the key because it often provides more detailed information. I had to go back to the PR4 release as it was already fixed in our HEAD branch.