How to implement lingui in a monorepo with expo and next js

[0-Sandy]

I'm working on a monorepo using create-t3-turbo, and I'm trying to share translations between /apps/nextjs and /apps/expo. I thought about creating a shared package in /packages/lang, but I'm not sure how to set everything up properly.

I looked at the Lingui monorepo guide, but it's almost empty and doesn't provide any concrete setup instructions.

Here's a simplified structure of my monorepo, it's not a complete listing, but it should give a general idea:

/apps
  /nextjs
  /expo
/packages
  /api
  /auth
  /db
  /ui
  /lang? ← (maybe this is where shared translations could live)
turborepo.json
pnpm-workspace.yaml
package.json

What I would like to do:

• Share the translation catalog (source and compiled) between both apps.
• Extract and compile messages from both /apps/nextjs and /apps/expo.
• Make the shared translations consumable via a single @acme/lang import.

Also, since both apps are in the monorepo, should I set up a separate lingui.config.js for /packages/lang? And how should the runtime i18n instance and I18nProvider be shared?

[timofei-iatsenko]

Create lingui.config.js and extract command in both apps in the monorepo. For each config file specify the paths need to be included, such as

for nextjs:

• apps/nextjs
• packages/*

For expo:

• apps/expo
• packages/*

If you have a package.json in your apps which is defining what packages from monorepo is used in particular app you can use this package.json to programatically build list of the folder to extract.

app/nextjs/package.json

"dependencies": {
   "@acme/ui": "workspace:^",
   "@acme/auth": "workspace:^"
}

Read package.json in the lingui.config.js and transform to:

• apps/nextjs
• packages/ui
• packages/auth

This will ensure you have a single source of truth (package.json) for the dependncy, and whenever packages/ui would be updated it will ensure Turbo will rerun apps/nextjs and re-extract catalogs

Don't create @acme/lang this will not make life easier.

Use some kind of TMS with a Translation Memory to manage translation for multiple catalogs in your monorepo.

This make sure all yours apps has own catalogs which includes only those messages they need.

You also can use a deps extractor per application, this way it will figure out automatically what packages are used in the app and extract only from them.

And how should the runtime i18n instance and I18nProvider be shared?

Define I18nProvider at both your apps, packages will just consume it.