When code is minified or transpiled, its original structure and readability are lost, making it hard to understand. A source map is a file that links the original source code to the processed code, allowing developers to see the original code while debugging.

Source maps are especially helpful for debugging. If an error occurs in the processed code, the source map helps developers trace it back to the exact spot in the original source code where the error started. This makes finding and fixing bugs much easier and more efficient.