Resolve .tsx + other extensions when importing .js / .jsx files

[karlhorky]

Bug description

Hi there, thanks for tsx, looks like a great project! 🙌

It would be great if tsx could also support the same module resolution that tsc does - specifically, resolving *.tsx files when a fully-specified .js ESM-style import is used.

tsc allows:

• .js to resolve .ts (supported by tsx)
• .js to resolve .tsx (unsupported by tsx)
• .jsx to resolve .ts (unsupported by tsx)
• .jsx to resolve .tsx (unsupported by tsx)
• (maybe others?)

Ref: microsoft/TypeScript#41887 (comment)

More details on what tsc and esbuild currently support

Reproduction

$ ls *.ts*
abc.tsx  def.ts  index2.ts  index.ts
$ cat index.ts
import abc from './abc.js';
console.log(abc);
$ cat abc.tsx
export default 'abc';

$ npx tsx index.ts
Error: Cannot find module './abc.js'
Require stack:
- /home/runner/JuicySphericalDistributedcomputing/index.ts
    at Function.Module._resolveFilename (node:internal/modules/cjs/loader:933:15)
    at Function.u.default._resolveFilename (/home/runner/JuicySphericalDistributedcomputing/node_modules/@esbuild-kit/cjs-loader/dist/index.js:1:1486)
    at Function.Module._load (node:internal/modules/cjs/loader:778:27)
    at Module.require (node:internal/modules/cjs/loader:1005:19)
    at require (node:internal/modules/cjs/helpers:102:18)
    at Object.<anonymous> (/home/runner/JuicySphericalDistributedcomputing/index.ts:1:17)
    at Module._compile (node:internal/modules/cjs/loader:1105:14)
    at Object.v (/home/runner/JuicySphericalDistributedcomputing/node_modules/@esbuild-kit/cjs-loader/dist/index.js:1:933)
    at Module.load (node:internal/modules/cjs/loader:981:32)
    at Function.Module._load (node:internal/modules/cjs/loader:822:12) {
  code: 'MODULE_NOT_FOUND',
  requireStack: [ '/home/runner/JuicySphericalDistributedcomputing/index.ts' ]
}

However, importing *.ts files using a fully-specified .js path works:

$ ls *.ts*
abc.tsx  def.ts  index2.ts  index.ts
$ cat index2.ts
import def from './def.js';
console.log(def);
$ cat def.ts
export default 'def';

$ npx tsx index2.ts
def

Replit demo (use the "Shell" tab): https://replit.com/@karlhorky/JuicySphericalDistributedcomputing#index.ts

Environment

  System:
    OS: Linux 5.15 Ubuntu 20.04.2 LTS (Focal Fossa)
    CPU: (8) x64 AMD EPYC 7B12
    Memory: 51.31 GB / 62.80 GB
    Container: Yes
    Shell: 5.0.17 - /bin/bash
  Binaries:
    Node: 16.15.0 - /nix/store/amm5j0ag985nh49n096a78q1dfs2xsfn-nodejs-16.15.0/bin/node
    Yarn: 1.22.18 - /nix/store/lccjrdddvk1bvd8zl29bd09df2z7d5p3-yarn-1.22.18/bin/yarn
    npm: 8.5.5 - /nix/store/amm5j0ag985nh49n096a78q1dfs2xsfn-nodejs-16.15.0/bin/npm
  npmPackages:
    tsx: ^3.9.0 => 3.9.0

Related issues

This is a superset of esbuild-kit/esm-loader#74

Can you contribute a fix?

• I’m interested in opening a pull request for this issue.

[jraoult]

I'm hitting the same issue. I suspect this will be solved when #344 is.

[mshima]

To fix this, you will need to patch the resolveTsPath and related mapper.
resolveTsPath will need to return an array so a core-utils breaking change or duplicate the function and deprecated the old to avoid the breaking change.

And change it's usage to handle the returned array in a loop at https://github.com/esbuild-kit/cjs-loader/blob/e7ba7caf42cb1bdceacb0bcafd2db3fd747931c0/src/index.ts#L179

[mshima]

#344 could be refactored to use this new resolveTsPath

[jraoult]

@mshima I have to confess I didn't try too hard to get into the details, but my use case is with ESM. I patched esm-loader with a rebased version of your PR (on top of main) and adding the .js to .tsx mapping worked like a charm for me.

[mshima]

@jraoult great, just saying the reproduction case is commonjs:

    at Module.require (node:internal/modules/cjs/loader:1005:19)

For esm, the PR change should fix the issue.

[karlhorky]

What extension resolutions do tsc and esbuild support?

See this Replit with a demo of what tsc supports: https://replit.com/@karlhorky/TypeScript-tsc-extension-resolution-js-jsx-cjs-mjs#index.ts

All of these extensions work (at least, they do not throw an error running tsc):

---

I also made a Replit with esbuild@0.15.10 on its own (no tsx or tsc) to test the resolution of all extensions (using --bundle mode), and it seems that they are all respected:

https://replit.com/@karlhorky/esbuild-extension-resolution-js-jsx-cjs-mjs#index.ts

[aredridel]

This affects our codebase too, with moduleResolution: "Node16", and our imports are fully specified .mjs, and it fails to look up the equivalent .mts.

[privatenumber]

@aredridel

The problem you're describing is different from what the issue is reporting.
Resolving .mjs -> .mts works: https://stackblitz.com/edit/node-3oq8qv?file=index.ts

Please open a new issue with reproduction if it doesn't work for you.

[karlhorky]

tsm implemented imports from the new file extensions over here, in case this is inspiration for an implementation in tsx:

• feat: import() in CommonJS & resolve virtual file extensions lukeed/tsm#43

[wesbos]

Also hitting this issue. Migrating a codebase to TypeScript and I'm importing a .ts file from a .js file.

tsc will follow a .js import to it's real .ts location. tsx wont - it complains the module is not found.

Using .ts extension fixes it in tsx, but then tsc` complains of not finding the file.

using tsx for dev and tsc to compile for production.

[karlhorky]

I'm importing a .ts file from a .js file

This sounds similar, but not really the same issue that I described above - I am not using any .js files.

Probably deserves a new issue for this, maybe also good to report one for tsm if it has the same behavior.

[privatenumber]

Yep, it's this: #135

[privatenumber]

All TypeScript extensions should be supported now in https://github.com/privatenumber/tsx/releases/tag/v4.0.0

Tests: https://github.com/privatenumber/tsx/blob/v4.0.0/tests/specs/smoke.ts#L515-L533

Hope this new release works well for you!

[karlhorky]

@privatenumber Thanks! Can confirm that tsx@4.0.0 works for our projects, which include imports with .js extensions which now resolve correctly to their .tsx files on disk.

[spearmootz]

im doing import x from "sample.js" the read file is sample.ts

i get Cannot find module. i have TSX version 4.6.2 on node 16.14.2