ESM – TypeError [ERR_UNKNOWN_FILE_EXTENSION]

[tolu]

I get this error when trying the typescript example with updated dependencies:

TypeError [ERR_UNKNOWN_FILE_EXTENSION]:
    Unknown file extension ".ts" for /home/tolu/github/uvu/examples/typescript/tests/math.ts

An image for context 😄

Single tests files can be run via:

node --loader ts-node/esm test/math.ts

[cspotcode]

Did you mean to use our ESM loader? node --loader ts-node/esm

This is a node issue; the only way to hook into node's ESM loading is with node's --loader flag. If you have a way to specify --loader then you should be able to use ts-node's ESM loader to handle resolution and compilation of .ts files.

[tolu]

Oh, I did not know about ts-node/esm, thanks! 🙏
but... I'm not specifically after using the ESM loader, I just want to get the typescript example in uvu working 😄 ESM or no-ESM.

That said, @cspotcode and I may be confusing things, but I thought that the dynamic import used by default here (uvu/run/index.mjs) WAS the ESM loader? And that since 0.5.0 this was enabled by default if hasImport in bin.js resolves to true?

So yes, I can run a single test-file at the time using node --loader ts-node/esm tests/math.ts, but how can I run the entire suite with uvu (not caring about ESM)?

[lukeed]

Hey, thanks!

What if the fix was to always use require/CommonJS mode if any -r/--require flag was defined?

As touched on here, ESM Node has --loader instead, and AFAIK cannot be hooked in outside of invoking node directly. And all require hooks need access to require.extensions (internal) in order to trigger X on loaded files.

[lukeed]

That said, we could still apply a form of the fix @tolu sent in #73 (thank you!) but that won't be the full story. For example, as of now, JSON modules.

I think the full fix is:

1. uvu forcing CommonJS on -r/--require defined:
   • guarantees shared internals [TypeError: Cannot read property 'push' of undefined #69]
   • only "affects" CLI usage
2. handling ERR_UNKNOWN_FILE_EXTENSION error
   • this should not happen given (1) but is a nice fallback to have

[tolu]

@lukeed all that sounds great to me, I must admit that the finer (if not all) points of ESM-loading and the usage of node flags pass at some distance above my head, but I'd be glad to make the suggested changes to the PR 👍

If not anything else I've certainly learned a lot trying to make sense of this 😄

[lukeed]

Cool. It's definitely in a weird-ish spot still. I'm working through it too (made clear here haha) Things definitely have progressed, but they definitely work better when it's all-or-nothing.

Just put the idea out there for now, to see if anyone can think of a reason why -r ~> CommonJS would be a terrible idea.
No need for changes at this time. I'll play with things & push any changes to your PR directly, if need be. Thanks!

[lukeed]

OK. The first "half" of the fix is now available in 0.5.1

If you still experience this issue after upgrading, please leave some information here so that it can reproduced!
Hopefully it's been resolved fully, but my suspicion that we've not seen the end of it... yet

[tolu]

works like a charm 🙏 🙇 thanks!

[lukeed]

Haven't had any issues at all with 0.5.1 (or heard of any).

I think we're good to go here. Can reopen in the future if something comes up.
Thanks!