Firefox DevTools美化模式下跳转至定义跳转到压缩JS是否为Bug？

Great question—this behavior could absolutely qualify as a bug, but let’s first rule out a few common configuration quirks that might be causing it:

Why This Might Be Happening #

• Source Map Problems
  Firefox DevTools relies heavily on source maps to connect minified code to its prettified/original counterpart. If the minified JS file doesn’t have a valid //# sourceMappingURL comment pointing to a correct source map, or if the source map itself is outdated or incomplete, DevTools might not know how to map your prettified view to a stable reference. When you click "Go to Definition", it falls back to the only concrete file it has: the minified version.

  • Quick check: Head to the Sources panel’s Page tab—do you see the unminified original source listed alongside the minified file? If not, the prettify button is just reformatting the minified code on-the-fly, not linking to a proper original source.

• On-the-Fly Prettify Limits
  If you’re using the {} "Prettify source" button on a minified file without a source map, Firefox is just doing a one-time reformat in the UI. This isn’t a persistent, linked source—so when you try to jump to a definition, DevTools can’t track the temporary prettified line numbers back to anything solid, and defaults to the original minified file. This feels like a bug because it’s inconsistent with user expectations, and it’s been reported by other developers before.

• Known DevTools Edge Cases
  This exact issue has popped up in Firefox’s bug tracker a few times. The core problem seems to be that DevTools doesn’t preserve the prettified state when navigating between positions in the same file. It’s less of a "critical bug" and more of an unpolished UI edge case, but it’s definitely not the behavior you’d expect.

How to Confirm It’s a Bug #

1. Test with a file that has a properly set up source map pointing to an unminified original. If "Go to Definition" correctly opens the unminified source, then the issue is definitely with how DevTools handles on-the-fly prettify.
2. Try the latest Firefox Nightly build—often these small UI navigation bugs get fixed in pre-release versions before rolling out to stable.

Temporary Workarounds #

• If you can, use source maps to load the original unminified sources directly. This is the most reliable way to debug with proper navigation support.
• If you have to use on-the-fly prettify, try searching for the function/variable name in the prettified code manually instead of relying on "Go to Definition".

内容的提问来源于stack exchange，提问作者Baba