How to extract source code of JavaScript map file exposed to production?
Did you aware of that?
What is exactly is the source map file?
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
So for the debugging purpose developers have enabled the below lines
//# sourceMappingURL=http://example.com/build.map
what exactly does webpack do?
When we use Webpack, Gulp, or browserify for bundling, transpilation, minification, and uglification.
For Detailed about webpack here: https://github.com/webpack/docs/wiki/usage
Now Let extract the source code from js.map
I have created a simple PHP file for extracting the source code from js.map file
Basically map file holds all files and source-code in JSON Format
Download this gist file (https://gist.github.com/Sturtuk/c74b41506d0ef71630eda2f1eb1adbbd)
rename the file in variable @ $file = ‘main.ff0058ad.js.map’;
I have downloaded from a random website, the map file size was 6mb
run > php your_php.php
See the Magic
Conclusion
Protect your source code and logic from production, Is not easy to copy code from minified files when some Idiot tries to convert
Better Safe Gaurd your Ideas
Secure your source map in production
Finally
You must have found this useful, “Press clap”.
