doc: history shows wrong version for conditional package export support

[gpoole]

📗 API Reference Docs Problem

• Version: 12.16.0

• Platform: All

• Subsystem: loader

Location

Modules: Packages

Affected URL(s):

• https://nodejs.org/api/packages.html#packages_exports

Description

Under the "history" section, the docs say that conditional export support was added and also unflagged in 12.16, which doesn't seem to be the case. 12.17.0 appears to be the first version that supports conditional exports and I can't get either conditional exports or the --experimental-conditional-exports flag to work in 12.16.0.

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[aduh95]

Conditional exports were added in #29978 and the flag was removed in #31001. It looks like that both PRs were indeed backported to v12.16.0. Maybe are you using another feature that was not backported until v12.17.0? Can you share a repro code that shows the feature is missing?

[github-actions]

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[gpoole]

I've created a reproduction here https://github.com/gpoole/node-missing-export-map. While I was doing that I think I realised the problem is actually that the conditional exports do work in 12.16, but only if the --experimental-modules option is set. So the output I get from the sample is:

12.16 with node index.js: missing map hello
12.17 with node index.js: common hello
12.16 with node --experimental-modules index.js: common hello

It seems that conditional exports are tied to module support. I think this makes sense, but I think the history section doesn't make it clear and to me it says that 12.16 uses conditional exports without any flags, which it doesn't.

[aduh95]

Thanks for the clarification, it's probably worth clarifying the documentation indeed. Do you see the same bahavior for package self-reference in Node.js v12.16.0?

[gpoole]

Yes, I see the same behaviour. After adding reference.cjs to the inner package I see the following:

cd node_modules/inner
node reference.cjs
# missing map hello
node --experimental-modules reference.cjs
# common hello
# (node:36203) ExperimentalWarning: The ESM module loader is experimental.