file is being assigned a //# sourceMappingURL but already has one

I just notice Firefox console outputs the following error for every single .js/.coffee file in my project (even the packages).

-file- is being assigned a //# sourceMappingURL, but already has one

Chrome's console doesn't show anything. I tried deleting all the .map files and clearing Firefox's cache but I'm still getting the errors.

Solution 1:

It's a warning (not an error) and it is a bug (~~https://bugzilla.mozilla.org/show_bug.cgi?id=1020846~~ fixed in FF 33)

This warning/error also applies to other libs (angular, backbone, etc.)

I have been working on a project for over a year now, I have never seen this message until roughly the last Firefox update.

I received it using jQuery 1.9.x, so I just updated my jQuery to 1.11.x and the error went away. I am now happy.

So, if you are using jQuery and see this Error/Warning, try updating your jQuery to the latest version.

Hope this helps someone.