tsconfig-paths does not work with ESM; possible switch to tsc-alias

[dyedwiper]

Is there an existing issue that is already proposing this?

• I have searched the existing issues

Is your feature request related to a problem? Please describe it

tsconfig-paths is used by the nest-cli to rewrite paths according to path aliases specified in tsconfig.json.

tsconfig-paths does not work with ES Modules as reported here e.g.:

• https://stackoverflow.com/questions/71571684/ts-node-with-tsconfig-paths-wont-work-when-using-esm
• Support for ts-node + tsconfig-paths + esm jonaskello/tsconfig-paths#243
• Unable to find module with tsconfig-paths when using esm: tsconfig-paths is incompatible with native ESM TypeStrong/ts-node#1375

Thus nest start throws an ERR_MODULE_NOT_FOUND when compiling to ES Modules and using path aliases. Here is a minimal example: https://stackblitz.com/edit/nestjs-typescript-starter-m27m4jmo

It is related to this issue: #1437. Though AFAIU the problem is not caused by the file extension. Thus I decided to open a new issue. Hope that's fine.

Describe the solution you'd like

A solution could be to use tsc-alias as a post-compilation step, instead of using tsconfig-paths in pre-compilation.

A possible benefit: Rewriting the paths with tsconfig-paths in pre-compilation involves some custom code which you could probably lose with tsc-alias.

I haven't fully tested it, but when I change the build script to "nest build && tsc-alias -p tsconfig.build.json", the import is correct in the compiled dist/app.module.js after running npm run build. See here: https://stackblitz.com/edit/nestjs-typescript-starter-rcmvukfp

Teachability, documentation, adoption, migration strategy

No response

What is the motivation / use case for changing the behavior?

We would like to use path aliases in a project and this hinders it at the moment.

[SrHadeSito]

+1

[fjodor-rybakov]

Only with swc works fine

{
  "$schema": "https://json.schemastore.org/nest-cli",
  "collection": "@nestjs/schematics",
  "sourceRoot": "src",
  "compilerOptions": {
    "builder": "swc",
    "deleteOutDir": true
  }
}

[fjodor-rybakov]

Another way just remove tsconfig-path and use import keyword.

For example:
My package.json

{
  "name": "myapp",
  "version": "0.0.1",
  "type": "module",
  "imports": {
    "#shared/*": ["./dist/shared/*"]
  }
}

and tsconfig.json

{
  "compilerOptions": {
    "module": "NodeNext",
    "declaration": true,
    "removeComments": true,
    "emitDecoratorMetadata": true,
    "experimentalDecorators": true,
    "allowSyntheticDefaultImports": true,
    "esModuleInterop": true,
    "target": "ES2024",
    "sourceMap": true,
    "outDir": "./dist",
    "baseUrl": "./",
    "strict": true,
    "skipLibCheck": true,
    "noImplicitAny": false,
    "strictBindCallApply": false,
    "forceConsistentCasingInFileNames": false,
    "noFallthroughCasesInSwitch": false,
    "useDefineForClassFields": false,
    "paths": {
      "#shared/*": ["./src/shared/*"]
    }
  },
  "include": ["src/**/*"]
}

And all works fine without rewriting paths