TypeError: Unknown file extension ".ts" - esmodules support

[AuroraLantean]

Original post in Anchor repo: [(https://github.com/solana-foundation/anchor/issues/1286)]

Anchor.toml [script] command:
test = "yarn run ts-mocha -p ./tsconfig.json -t 1000000 tests/**/*.ts"

The problem is the m1.ts file cannot import functions from another ts file!!!???
in my utils.ts

export const log1 = console.log;

in my m1.ts file:

import { log1 } from './utils';
describe('scenario1', async () => {
  it('initialize', async () => {
    log1('\n---------== init');
  });
});

the imported log1 function or any other function will cause the Unknown file extension ".ts" error!!??

my local package dependencies:
"mocha": "^9.1.3",
"ts-mocha": "^9.0.0-alpha1",
"ts-node": "^10.4.0",
"typescript": "^4.5.4"

Please advise. Thank you

[piotrwitek]

please test with new v9.0.0
9.0.0-alpha1 is experimental

[AuroraLantean]

Thank you for your post... but "ts-mocha": "9.0.0" results in the same error as above.

[piotrwitek]

@AuroraLantean need a little bit of help, if you could help me to create a simple repo with your setup (package.json and m1.ts + utils.ts files and npm test command) I would try to investigate that repo and fix that issue and also look for a way to add it to the regression testing for your use-case. 

I guess it's related to the ts-node version, not sure why you have installed it in your project but it's different from ts-mocha version possibly clashing.

[AuroraLantean]

Hi @piotrwitek , thank you for your quick reply. Please take the following code:
https://github.com/AuroraLantean/SolanaAnchorDemo2
Thank you!

[Burwin]

For another example, I was able to reproduce it with the following repo after installing/using dateformat: https://github.com/Burwin/ts-mocha-file-extension

[simonbuchan]

Pretty sure this is due to type: module in package.json (possibly in a dep). See the ts-node issue for this.

Not sure how to mangle ts-mocha into doing the right thing here? Something like node --loader=ts-node/esm ts-mocha ... should be enough, but doesn't work for me, perhaps ts-mocha needs to support --loader itself?

[cn-ia]

Try ts-mocha -n loader=ts-node/esm -p tsconfig.json tests/**/*.test.ts via npm scripts, it works for me!
(Optional) Check npx ts-mocha --help for more details of this option.

[DoodahProductions]

Hello, having the same issue here. Trying @cn-ia solution did not work for me

[DoodahProductions]

If that can help, I found out that this issue seems to be triggered when I do use the package get-port version >= ^6.0.0
If I do remove this package, tests are running correctly. If I add this package, then my test command produce the error TypeError [ERR_UNKNOWN_FILE_EXTENSION]: Unknown file extension ".ts"

Test command :

"test": "ts-mocha -p tsconfig.json 'test/**/*.ts'",

TsConfig:

{
  "compilerOptions": {
    "module": "commonjs",
    "target": "es6",
    "composite": true,
    "outDir": "dist",
    "rootDir": ".",
    "sourceMap": true,
    "strict": false,
    "declaration": true,
    "esModuleInterop": true,
    "resolveJsonModule": true
  },
  "include": [
    "./**/*.ts",
    "src/definitions/**/*.json",
    "src/modules/tasks"
  ],
  "exclude": [
    "node_modules",
    "dist",
    "test"
  ]
}

[sagrawal31]

Pretty sure this is due to type: module in package.json (possibly in a dep). See the ts-node issue for this.

Not sure how to mangle ts-mocha into doing the right thing here? Something like node --loader=ts-node/esm ts-mocha ... should be enough, but doesn't work for me, perhaps ts-mocha needs to support --loader itself?

For me, this was the problem. Removing "type": "module" from package.json fixed the problem for me.

[SmashingQuasar]

Hey! I have the same issue. I do not have "type": "module" in my package.json so it might be something else. Honestly my package.json is extremely simple so it's doubtful that it originates from there. I'm using ts-mocha version 10.0.0 and ts-node version 10.7.0.

[felipeplets]

@SmashingQuasar I believe the issue is because ts-mocha depends on 1ts-node@7.0.11 which didn't support ESM it would need to depend on 10+ or to have it as a peer dependency although that would force all developers to install ts-node themselves even if they don't use ts-node for other reasons.

If you run npm ls ts-node in your project you should see something like:

@my-project@ /Users/myuser/projects/my-project
├─┬ ts-mocha@10.0.0
│ └── ts-node@7.0.1
└── ts-node@10.7.0

Showing that although your project uses a newer ts-node version ts-mocha still uses an older version.