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Possible ImprovementThe current behavior isn't wrong, but it's possible to see that it might be better in some casesThe current behavior isn't wrong, but it's possible to see that it might be better in some cases
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Description
Bug Report
🔎 Search Terms
CommonJS, allowJS, ESM, CJS, file extensions
🕗 Version & Regression Information
- This is the behavior in every version I tried, and I reviewed the FAQ for entries about output "file extensions for CommonJS modules".
⏯ Playground Link
Sandbox link with relevant code (I couldn't use the playground, since this involves using an .mjs file).
💻 Code
// package.json
{
"name": "tsc-mjs-extension-bug",
"version": "0.1.0",
"type": "commonjs",
"main": "dist/javascript.mjs",
"scripts": {
"build": "tsc",
"test": "node ."
},
"dependencies": {
"typescript": "5.1.3"
}
}
// tsconfig.json
{
"compilerOptions": {
"module": "commonjs",
"moduleResolution": "nodenext",
"allowJs": true,
"outDir": "dist"
}
"include": ["src"]
}
// src/javascript.mjs
export const where = "javascript";
console.log(`Hello ${where}`);
// src/typescript.ts
export const where = "typescript";
console.log(`Hello ${where}`);
🙁 Actual behavior
The javascript.mjs
is transformed to CommonJS (as expected), but the file extension of the emitted file is still .mjs
.
This breaks the package, since .mjs
is supposed to be use exclusively for JavaScript using ESM and the emitted file now uses CommonJS.
🙂 Expected behavior
I would expect tsc
to transform the src/javascript.mjs
to CommonJS and either:
- emit it as
dist/javascript.cjs
or alternatively - take into account the
"type": "commonjs"
in the package.json and emit the file as.js
as it does with thesrc/typescript.ts
file.
takameyer and elle-jknightedcodemonkeytakameyer
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Possible ImprovementThe current behavior isn't wrong, but it's possible to see that it might be better in some casesThe current behavior isn't wrong, but it's possible to see that it might be better in some cases