https://github.com/jakobjingleheimer/correct-ts-specifiers
correct erroneous file extensions in typescript import specifiers
https://github.com/jakobjingleheimer/correct-ts-specifiers
ecma importstatements migration-tool nodejs typescript
Last synced: about 1 year ago
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correct erroneous file extensions in typescript import specifiers
- Host: GitHub
- URL: https://github.com/jakobjingleheimer/correct-ts-specifiers
- Owner: JakobJingleheimer
- Created: 2024-08-14T19:55:17.000Z (almost 2 years ago)
- Default Branch: main
- Last Pushed: 2024-11-21T20:16:26.000Z (over 1 year ago)
- Last Synced: 2025-03-24T03:53:10.723Z (about 1 year ago)
- Topics: ecma, importstatements, migration-tool, nodejs, typescript
- Language: TypeScript
- Homepage:
- Size: 108 KB
- Stars: 6
- Watchers: 2
- Forks: 1
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
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README
# Correct TypeScript Specifiers
This package transforms import specifiers in source-code from the broken state TypeScript's compiler (`tsc`) required (prior TypeScript v5.7 RC) into proper ones. This is useful when source-code is processed by standards-compliant software like Node.js. This is a one-and-done process, and the updated source-code should be committed to your version control (ex git); thereafter, source-code import statements should be authored compliant with the ECMAScript (JavaScript) standard.
> [!TIP]
> Those using `tsc` to compile will need to enable [`rewriteRelativeImportExtensions`](https://www.typescriptlang.org/tsconfig/#rewriteRelativeImportExtensions); using `tsc` for only type-checking (ex via a lint/test step like `npm run test:types`) needs [`allowImportingTsExtensions`](https://www.typescriptlang.org/tsconfig/#allowImportingTsExtensions) (and some additional compile options—see the cited documentation);
This package does not just blindly find & replace file extensions within specifiers: It confirms that the replacement specifier actually exists; in ambiguous cases (such as two files with the same basename in the same location but different relevant file extensions like `/tmp/foo.js` and `/tmp/foo.ts`), it logs an error, skips that specifier, and continues processing.
> [!CAUTION]
> This package does not confirm that imported modules contain the desired export(s). This _shouldn't_ actually ever result in a problem because ambiguous cases are skipped (so if there is a problem, it existed before the migration started). Merely running your source-code after the mirgration completes will confirm all is well (if there are problems, node will error, citing the problems).
> [!TIP]
> Node.js requires the `type` keyword be present on type imports. For own code, this package usually handles that. However, in some cases and for node modules, it does not. Robust tooling already exists that will automatically fix this, such as [`consistent-type-imports` via typescript-lint](https://typescript-eslint.io/rules/consistent-type-imports) and [`use-import-type` via biome](https://biomejs.dev/linter/rules/use-import-type/). If your source code needs that, first run this codemod and then one of those fixers.
## Running
> [!CAUTION]
> This will change your source-code. Commit any unsaved changes before running this package.
```sh
npx codemod@latest correct-ts-specifiers
```
If you're using `tsconfig`'s `paths`, you will need a loader like [`@nodejs-loaders/alias`](https://github.com/JakobJingleheimer/nodejs-loaders/blob/main/packages/alias?tab=readme-ov-file)
```sh
npm i @nodejs-loaders/alias
NODE_OPTIONS="--loader=@nodejs-loaders/alias" \
npx codemod@latest correct-ts-specifiers
```
## Supported cases
* no file extension → `.cts`, `.mts`, `.js`, `.ts`, `.d.cts`, `.d.mts`, or `.d.ts`
* `.cjs` → `.cts`, `.mjs` → `.mts`, `.js` → `.ts`
* `.js` → `.d.cts`, `.d.mts`, or `.d.ts`
* [Package.json subimports](https://nodejs.org/api/packages.html#subpath-imports)
* [tsconfig paths](https://www.typescriptlang.org/tsconfig/#paths) (requires a loader)
* Commonjs-like directory specifiers
Before:
```ts
import { URL } from 'node:url';
import { bar } from '@dep/bar';
import { foo } from 'foo';
import { Bird } from './Bird'; // a directory
import { Cat } from './Cat.ts';
import { Dog } from '…/Dog/index.mjs'; // tsconfig paths
import { baseUrl } from '#config.js'; // package.json imports
export { Zed } from './zed';
export const makeLink = (path: URL) => (new URL(path, baseUrl)).href;
const nil = await import('./nil.js');
const bird = new Bird('Tweety');
const cat = new Cat('Milo');
const dog = new Dog('Otis');
```
After:
```ts
import { URL } from 'node:url';
import { bar } from '@dep/bar';
import { foo } from 'foo';
import { Bird } from './Bird/index.ts';
import { Cat } from './Cat.ts';
import { Dog } from '…/Dog/index.mts'; // tsconfig paths
import { baseUrl } from '#config.js'; // package.json imports
export type { Zed } from './zed.d.ts';
export const makeLink = (path: URL) => (new URL(path, baseUrl)).href;
const nil = await import('./nil.ts');
const bird = new Bird('Tweety');
const cat = new Cat('Milo');
const dog = new Dog('Otis');
```