If you're using Firefox 52 or later and need to switch back to the old Debugger, you can do so by visiting about:config and setting the "devtools.debugger.new-debugger-frontend" preference to
- sources are often combined and minified to make delivering them from the server more efficient.
In these situations, it's much easier to debug the original source, rather than the source in the transformed state that the browser has downloaded. A source map is a file that maps from the transformed source to the original source, enabling the browser to reconstruct the original source and present the reconstructed original in the debugger.
To enable the debugger to work with a source map, you must:
- generate the source map
- include a comment in the transformed file, that points to the source map. The comment's syntax is like this:
In the Debugger's source list pane, the original CoffeeScript source now appears as "main.coffee", and we can debug it just like any other source.