Is it possible to reverse a Vite production build back to source code without a source map?

[Cihatata]

Hi Vite team,

I'm currently analyzing a JavaScript file generated from a Vite production build. Unfortunately, the source map is not available. The output is fully minified and includes renamed variables (e.g., a, b, c) (obfuscated), inline JSX transformed via the automatic runtime (e.g., jsx / jsxs), and tree-shaken modules bundled in a single file.

My question is:
Is there any reliable or recommended way to reverse-engineer the build output back into something close to the original source (especially for debugging or auditing purposes) when no source map is available?

I'm aware that full recovery is likely impossible, but I'm wondering.
Thanks in advance!

[SametDulger]

Hi,

Reversing a Vite production build back to something close to the original source without source maps is inherently very difficult. Because:

The code is minified, so variable names are shortened and structure is compressed.

Tree-shaking removes unused code, changing the shape of the output.

JSX and other syntax are transformed into runtime calls, which look quite different from the original code.

There isn’t a reliable or recommended way to fully recover the original source from the bundled output without source maps.

Your best bet for debugging or auditing is:

Use source maps whenever possible. They’re designed exactly for this purpose.

If you don’t have source maps, you can try using JavaScript beautifiers or deminifiers (like Prettier or online tools) to get a more readable format, but this won’t restore meaningful variable names or original structure.

Look for comments or clues in the bundle (sometimes dev builds or partial builds include them).

If you control the build, enabling source maps is the way to go for future debugging.

In summary, without source maps, you can improve readability slightly with prettifiers, but there’s no tool that can reliably reverse-engineer minified Vite output back to original source.