Auto rewrite/transform TypeScript import path from tsconfig.paths

[muuvmuuv]

Would be nice if Biome could auto fulfill import paths to tsconfig.compilerOptions.path. Maybe with a threshold option when it should do it:

import { IconComponent } from '../../component/icon'

becomes:

import { IconComponent } from '@/component/icon'

but:

import { IconComponent } from './icon'
import { IconComponent } from '../icon'

with a threshold of 1 wouldn't transform.

Since this would require a lot of I/O work it should be a flag/option.

[damianobarbati]

Does this exist now @muuvmuuv?

[ematipico]

I am not sure what this proposal is about. The title talks about formatting, but then the body explains that an import should be transformed into another path based on an external file.

Which one is it? The transformation doesn't seem feasible though, because it creates code that isn't portable.

[damianobarbati]

@ematipico here @muuvmuuv is referring to rewriting the paths respecting the tsconfig.json. I'm having the same problem lately.

For instance, if I have my Service.ts

import Foe from "../../types/src/Foe.ts"

Then I change tsconfig.json to add:

    "paths": {
      "@api/*": ["./services/api/src/*"],
      "@webapp/*": ["./services/webapp/src/*"],
      "@type/*": ["./services/types/src/*"]
    }

I would like biome to rewrite in Service.ts:

import Foe from "@types/Foe.ts"

Desiderata would be:

1. Biome rewriting paths respecting the subpath imports in package.json if any.
2. Biome rewriting paths respecting the tsconfig path in tsconfig.json if any.
3. @muuvmuuv suggests to add a threshold preventing the rewrite based on hierarchy: for instance 1 means don't rewrite if file referenced is in same directory, 2 if file referenced is in parent directory, etc... (the threshold is the .... dots in hierarchy).

The point 1 is needed for the new --experimental-strip-types flag to work with relative paths: it won't support rewriting code as tsx does, so developers will probably (my guess) start using more and more the native subpath import feature of node.

[ematipico]

I see, thank you for detailed explanation.

We're still far away from being able to provide such functionality, as we miss the required infrastructure, so you'll have to wait a bit more.

[damianobarbati]

@ematipico definitely not urgent but a nice to have, thank you for the feedback! 🚀

[muuvmuuv]

Changed the title, format wasnt the correct naming :)