Make it possible to pass rootDirs and paths via cli

[Psy-Kai]

Suggestion

🔍 Search Terms

• tsc cli "rootDirs"

✅ Viability Checklist

My suggestion meets these guidelines:

• This wouldn't be a breaking change in existing TypeScript/JavaScript code
• This wouldn't change the runtime behavior of existing JavaScript code
• This could be implemented without emitting different JS based on the types of the expressions
• This isn't a runtime feature (e.g. library functionality, non-ECMAScript syntax with JavaScript output, new syntax sugar for JS, etc.)
• This feature would agree with the rest of TypeScript's Design Goals.

⭐ Suggestion

It should be possible to pass --rootDirs and --paths via CLI. This would make it easier to integrate with (non-js)-buildtools, which just call the CLI.

📃 Motivating Example

Make it easier to use the tsc-cli with arbitrary build-tools in big projects without using a tsconfig.json.

💻 Use Cases

My specific use-case is a project with generated files (protobuf). I want to generate the files into a build/dist directory but need a way for referencing the file properly (which I would do with rootDirs or the baseUrl, paths pair). I also want to use a buildtool which just calls the tsc-cli for every file (like when compiling C-sourcecode).

[Psy-Kai]

Another approach would be #27379 and just use the compilerOptions.

[kkmuffme]

+1

The workaround doesn't work when you want to run tsc for a single file only without having to create a separate (extending) tsconfig all the time.

[HolgerJeromin]

To give some context:
The doc pretends that this is possible. But using that results in

error TS6064: Option 'paths' can only be specified in 'tsconfig.json' file or set to 'null' on command line.

The syntax is working with typeRoots though...