Custom loader not called on node 20

[enricoschaaf]

Please provide details about:

• What you're trying to do
  Load a typescript test file
• What happened
• TypeError [ERR_UNKNOWN_FILE_EXTENSION]: Unknown file extension ".ts" for example.test.ts
• What you expected to happen
  the typescript loader to be called and handeling the file

Please share relevant sample code. Or better yet, provide a link to a minimal reproducible example.

We'll also need your AVA configuration (in package.json or ava.config.* configuration files) and how you're invoking AVA. Share the installed AVA version (get it by running npx ava --version).

"ava": {
"extensions": {
"ts": "module"
},
"nodeArguments": [
"--loader=tsx"
]
}

node version 20.3.0 ava verison 5.3.0

[novemberborn]

I reckon the problem is somewhere between Node.js, the loader and the configuration; not AVA itself.

One possibility is that with your configuration ("ts": "module") the test file is loaded through import() not require(). The loader may be CJS only. Try "ts": "commonjs" .

[transitive-bullshit]

Running into the same issue which only repros on Node.js v20.

Here's a workaround, but something changed between Node v19 and v20 which is causing this.

[novemberborn]

Once that's in a Node.js version, we could make it an experimental feature in AVA. This means it needs to be explicitly opted in to (and we make no reliability guarantees). But then once it's stable in Node.js it's a straight-forward change to make it stable in AVA as well.

[tommy-mitchell]

Looks like it's coming in Node.js 20.6: nodejs/node#49185

[tommy-mitchell]

So this has since released. How are experimental features in AVA developed?

[tommy-mitchell]

@novemberborn friendly bump :) how should we go about adding this feature? (Or is there a better way?) Seems like it's primarily register(loader) from node::module, but I'm not entirely sure what all it entails.

[novemberborn]

Once it's stable, the next question is whether AVA needs to provide anything for this or if it can be done through the require config.

[JAForbes]

I managed to get it to work, but it is weird:

// ava.config.js
export default {
	extensions: {
		js: true,
		ts: 'commonjs' // but still write your tests in esm
	}
}

npx tsx node_modules/.bin/ava

For some reason --loader=tsx, or --loader=tsx/esm didn't work, but just letting tsx run ava solves it. The ts:commonjs feels wrong because my test files are actually using esm, but without setting that, ava didn't automatically find the .ts test files.

I'm guessing tsx is transpiling to cjs which is why ts: 'commonjs' has to be set.

I wish this wasn't the solution 😅

[Sparticuz]

After lots of combo's, I've got working tests with the following:

$ node --version
v20.10.0

{
  "type": "module",
  "scripts": {
    "test": "c8 ava"
  },
  "ava": {
    "extensions": {
      "ts": "module"
    },
    "nodeArguments": [
      "--import=tsx/esm"
    ]
  },
"devDependencies" {
    "ava": "5.3.1",
    "c8": "^8.0.1",
    "tsx": "4.2.1",
  }
}

ava is pinned because I'm having issues with the non-automatic process closing #3279
tsx is pinned because of the 100% issue privatenumber/tsx#433

[xfoxfu]

@Sparticuz I am having difficulties following your setup. Would you please offer your tsconfig.json for a reference?

[Sparticuz]

Actually, was still having difficulties, but I just switch to tsimp instead of tsx and it seems to be better

-        "tsx": "^4.2.1",
+        "tsimp": "^2.0.10",

Now my only issue is ava not auto-closing

[codan84]

Thanks for the above, this worked for me on node 20:

{
  cache: false,
  failWithoutAssertions: false,
  extensions: {
    ts: 'module'
  },
  nodeArguments: [
    '--import=tsimp/import',
    '--import=testdouble'
  ]
}

[vashian]

It works for me, thanks!

[yuriy-yarosh]

@Sparticuz fyi TSX is on esbuild, so doesn't support decorators hence TypeORM and MikroORM.

[RangerMauve]

I switched my CI to use node 19.x as a quickfix