ts-node gives type errors, presumably doesn't load .d.ts file, when allowJs && checkJs

Expected Behavior

Code compiles.

Actual Behavior

Gives type error, saying variable implicitly has an any type.

Steps to reproduce the problem

1. Create a library with type declarations:

   // foo.js
   export function foo({ foo }) {
      console.log(`Inside foo({foo:${foo}})`);
   }
   // foo.d.ts
   export declare function foo({ foo }: {
      foo: number;
   }): void;
   // package.json
   {
     "name": "foo",
     "version": "1.0.0",
     "main": "foo.js",
     "types": "foo.d.ts",
     "type": "module",
     "license": "MIT"
   }
   

2. Create a TS project, set allowJs, checkJs to true.
3. import the library and call foo({foo:100})
4. Run tsc, it compiles without any error.
5. Run node --loader ts-node/esm main.ts

Output:

TSError: ⨯ Unable to compile TypeScript:
../myapp-foo/foo.js:1:23 - error TS7031: Binding element 'foo' implicitly has an 'any' type.

1 export function foo({ foo }) {

Minimal reproduction

https://github.com/itsfarseen/ts-node-repro

Specifications

ts-node v10.1.0
node v16.5.0
compiler v4.3.5

tsconfig.json: https://github.com/itsfarseen/ts-node-repro/blob/main/myapp-bar/tsconfig.json

Operating system and version: Arch Linux

[cspotcode]

Whenever you require a file and ts-node needs to compile it, the file is manually added to the “files” array as needed to ensure TypeScript looks at it and emits compiled code.

I suspect this is happening: tsc will not look at the .js file because it has instead resolved to the .d.ts file. ts-node, on the other hand, has seen a require() which resolved to the js file, so it has forced the .js file to be included in your “files” array.

tsc --listFiles will show the files pulled into compilation. tsc –traceResolutions will explain why they are pulled into compilation.

*Above, “files” array refers to the array in tsconfig.json

On Mon, Aug 9, 2021, 1:50 AM Blake Embrey @.***> wrote:

I’m not really an expert on TypeScript when it comes to the JS features, but based on this https://www.typescriptlang.org/docs/handbook/intro-to-js-ts.html I believe it’s basically doing type-checking on your JavaScript (almost) as if it’s TypeScript.

— You are receiving this because you commented. Reply to this email directly, view it on GitHub https://github.com/TypeStrong/ts-node/issues/1421#issuecomment-894966816, or unsubscribe https://github.com/notifications/unsubscribe-auth/AAC35OA3MJBHWY273PE5AL3T35UD7ANCNFSM5BXNYTRQ .

[blakeembrey]

Update: I was using the scope option wrong (trying to give it a directory instead of a boolean). This works for me:

TS_NODE_SCOPE=true node --loader ts-node/esm main.ts

You can also add this to your tsconfig.json too:

"ts-node": {
  "scope": true
}