Missing noEmit: true from default tsconfig.json in type stripping docs

[styfle]

Affected URL(s)

https://nodejs.org/api/typescript.html#type-stripping

Description of the problem

The recommended tsconfig.json is missing noEmit: true.

Is seems very likely that a user who chooses to author in TS over JS will also want to type check their code.

And if you forget noEmit: true, then you'll accidentally emit JS, which is not needed.

[styfle]

cc @marco-ippolito @nodejs/typescript in case there is a reason this was omitted. I search existing issues and prs but didn't find a reason.

I can create a PR if we want to add, noEmit: true, just let me know 🤓

[marco-ippolito]

Since the feature is experimental we'd want to encourage users to transpile, and I generally Id always encourage users to transpile 😆

[robpalme]

I think there's two separate use-cases that we cannot express in a single tsconfig.json.

1. Always directly execute source (noEmit)
   • This will work fine for simple things like build scripts written as *.ts files that will never need to be distributed/published.
2. Situational execution (rewriteRelativeImportExtensions)
   • During development: Direct execution of source
   • For production/publication: Compile-to-JS

IMO both use-cases are legitimate. Use-case 1 (that @styfle is referring to) is simpler so some folk might prefer it.

[styfle]

simple things like build scripts written as *.ts files that will never need to be distributed/published

This is exactly the case I ran into.

I have a large build script in JS and it had a bug so I wanted to convert to TS to catch the bug for future authors. Perfect use case for strip types. But then after following the docs, I realized it was emitting JS 😓

I guess I'm having trouble understanding the other use case of why strip types if you plan to use tsc to transpile?

[marco-ippolito]

I guess I'm having trouble understanding the other use case of why strip types if you plan to use tsc to transpile?

faster development cycle, no need to wait for tsc to transpile as you develop
We could propose two config, one for transpiling one for not traspiling

[styfle]

Yeah two configs might work. Or one config with an optional comment like:

{
  "compilerOptions": {
     "noEmit": true, // Optional - prevent tsc from emitting transpiled JS
     "target": "esnext",
     "module": "nodenext",
     "allowImportingTsExtensions": true,
     "rewriteRelativeImportExtensions": true,
     "erasableSyntaxOnly": true,
     "verbatimModuleSyntax": true
  }
} 

I can create a PR after #57271 merges.

[jakebailey]

Yeah, I would just include a note, though I would suggest making it mention "if you are publishing" or something.

[styfle]

I created a PR:

• doc: recommend setting noEmit: true in tsconfig.json #57320