Source Maps

Source Map documentation

Closure Compiler can produce source maps to aid in debugging. These are created when the --create_source_map flag is used. While the compiler also has the --source_map_input flag which allows the compilation to be aware of previous transformations, input source maps are only utilized to display error messages and do not affect the output source map.

You can pass source maps for input files to the compiler with the --source_map_input flag. The npm gulp plugins utilize the gulp-sourcemaps plugin.

Notes regarding source map generation and consumption.

Design docs here:

Source Map v3

Design docs for deprecated versions:

Source Map v2

Source Map v1

Implementation here:

com.google.debugging.sourcemap

Mozilla's JS Implementation here:

https://github.com/mozilla/source-map

Webkit JS Implementation here:

http://trac.webkit.org/browser/trunk/Source/WebInspectorUI/UserInterface/Models/SourceMap.js#L158

Blink JS Implementation here:

https://code.google.com/p/chromium/codesearch#chromium/src/third_party/WebKit/Source/devtools/front_end/sdk/SourceMap.js&type=cs&l=282

Discussions:

dev-js-sourcemap@lists.mozilla.org

Chrome's support of Source Maps discussed:

http://www.html5rocks.com/en/tutorials/developertools/sourcemaps/

A SourceMap encoding/decoding debugger: http://murzwin.com/base64vlq.html