compileNamespace should take package.json "type" into account

[lukescott]

When you set "type": "module" in your JSON both .js and .ts files (if you are using TypeScript) are considered modules. You only need to use the .m[jt]s or .c[jt]s extensions as an override.

I bring this up because it also applies to TypeScript, not just vanilla JavaScript. And both can have module.exports = or export const depending on the combination of package type and extension used.

I'm running into issues with babel when compiling code with a mix of .ts and .cts extensions. Babel just compiles everything to .js. There doesn't seem to be a way to solve this.

Also, newer node versions unfortunately are extremely strict about this, so if you don't use the right syntax it just fails.

I would like to propose reading the package.json type and use the following logic:

• If module and compileNamespace is "cjs", write module.exports = to a .cjs file
• If module and compileNamespace is "es", write export const messages = to a .js file
• If module and compileNamespace is "ts", write export const messages: AllMessages = to a .ts file
• If commonjs and compileNamespace is "cjs", write module.exports = to a .js file
• If commonjs and compileNamespace is "es", write export const messages = to a .mjs file
• If commonjs and compileNamespace is "ts", write export const messages: AllMessages = to a .mts file

If this is too complicated I understand. Ideally Lingui would just have a "typescript" option and just detect the package.json type. And optionally be able to provide a custom compilation function.

[gadicc]

In the meantime, just posting the script I'm using as a workaround in package.json for { "type": "module" }:

{
  "scripts":
    "i18n:compile": "lingui compile && for file in locales/*/messages.js; do sed -i 's/module.exports={messages:\\(.*\\)};$/export const messages = \\1;/' $file ; done",
}

It changes from module.exports = { messages: {} } to export const messages = {} (it could just as easily rename the file to .cjs).

[timofei-iatsenko]

@lukescott i think it would be more straightforward and easy to understand/use if we add a bunch of new parameters instead of one namespace and reading implicitly the "type": "module".

lingui compile --modules=cjs --extension=js => write module.exports = to a .js file
lingui compile --modules=esm --extension=mjs => write export const messages = to a .mjs file
lingui compile --modules=esm --extension=mts --typescript => write export const messages: AllMessages = to a .mts file

What do you think?

[vonovak]

I'd also rather make this explicitly configurable, as opposed to trying to infer from package.json file. In monorepos with multiple package.json files that approach would be problematic.

[stabildev]

In the meantime, just posting the script I'm using as a workaround in package.json for { "type": "module" }:

{
  "scripts":
    "i18n:compile": "lingui compile && for file in locales/*/messages.js; do sed -i 's/module.exports={messages:\\(.*\\)};$/export const messages = \\1;/' $file ; done",
}

It changes from module.exports = { messages: {} } to export const messages = {} (it could just as easily rename the file to .cjs).

Thanks, this slight variation works for me:

"compile": "lingui compile && for file in locales/*/messages.js; do sed -i '' 's/module.exports=\\({messages:.*}\\);/export const messages = \\1;/' $file; done"

Would be great to have a --modules=esm option