add api to detect whether source-maps are enabled

[sapphi-red]

What is the problem this feature will solve?

#39085 added process.setSourceMapsEnabled to enable source-maps programmatically. This is helpful for tools like Vite, thank you for implementing. 💚

But as this was implemented we now cannot know whether source-maps are enabled. I guess it was possible by process.execArgv.includes('--enable-source-maps') previously.

What is the feature you are proposing to solve the problem?

Add process.getSourceMapsEnabled that returns whether the source-maps are enabled.

What alternatives have you considered?

Add a getter + setter named process.isSourceMapsEnabled that works like process.getSourceMapsEnabled and process.setSourceMapsEnabled.

[bnoordhuis]

I read through the linked vite pull request but it wasn't clear to me why you need to know whether source maps are enabled. Can you explain? What's the use case?

[sapphi-red]

Thanks for the response!

Vite exports a function that rewrites Error::stack to make the stack trace point to the original source file using source maps. When source maps are enabled on Node.js, Error::stack contains a stack trace that already points to the original source file. If the Error::stack already points to the original source file, that function should be no-op.

Because Vite nor the script using Vite knows whether the stack trace points to the original source file or the transformed file, we cannot make that function no-op.

// this is a pseudocode and won't work
import { load, rewriteStacktrace } from 'vite'

const mod = await load('./foo.js')

try {
  mod.error()
} catch (e) {
  console.log(e.stack) // this stack trace points to the transformed file
  rewriteStacktrace(e) // rewrite the stack trace
  console.log(e.stack) // this stack trace points to the original source file
}

[bnoordhuis]

Right, that makes sense. getSourceMapsEnabled() already exists internally but would it work for you? It enables, as a side effect, source maps on first call when --enable-source-maps is set.

[sapphi-red]

getSourceMapsEnabled() would work for me.

I know I should avoid using internal things, but is there any way to access the internal getSourceMapsEnabled()? If it's possible, I can support older versions.

[bnoordhuis]

It's not exposed in any way (I think) but pull request welcome. I wouldn't object to a side-effect-free process.sourceMapsEnabled getter either; maybe that's even better.

[github-actions]

There has been no activity on this feature request for 5 months and it is unlikely to be implemented. It will be closed 6 months after the last non-automated comment.

For more information on how the project manages feature requests, please consult the feature request management document.