From:  Andy Sterland <Andy.Sterland@microsoft.com>
Date:  16 Apr 2014 07:25:47 Hong Kong Time
Newsgroup:  news.mozilla.org/mozilla.dev.js-sourcemap
Subject:  

IE11 F12 developer tool for source maps

NNTP-Posting-Host:  63.245.216.66

Just thought I'd share that the latest update to IE included support* for source maps in the F12 developer tools (blog). Something that has been a long time coming :). The feature is at the moment just for debugging JavaScript and there isn't any source map magic for CSS.

Anyway I'm looking forward to posting more to this group as we're keen to improve on the experience debugging code that's been compiled/minified/transformed.

-Andy

*For full disclosure there is a few parts of the spec that we haven't yet implemented:

sourcesContent
Currently the F12 support for source maps doesn't include support for sources that are embedded in the map via sourcesContent. This is a feature we'd like to add at a later date though we have some reservations about how tools would discover the 'language' for embedded sources (which is a more general problem).  Something that's worth a separate thread at a later date.

Index Maps
Currently the F12 support for source maps doesn't include any support for index maps. Alas this was something we noticed too late for us to add it in time, though there's also some reservations on that team on how multi-level mapping should work. Something that's worth a separate thread at a later date.

Relative path resolution for //# sourceURL
In cases where executed code has a //# sourceURL comment F12 doesn't resolve the map file relative to it. For example if some code is evaluated that ends with:
//# sourceURL=./path/to.js
//# sourceMappingURL=./path/to.js.map
The sourceMappingURL is resolved relative to the HTML document not the "./path/to.js" this is a bug that we'll fix in a future release.