fix: changes and fixes for Turbopack Support

[aralroca]

Fixes #91

Changes and Fixes for Next Translate Turbopack Support

This document summarizes the changes made to the next-translate-plugin to resolve translation issues and crashes when using Next.js with Turbopack, specifically addressing the basic, complex, and without-loader examples.

Key Fixes

1. Absolute Path Correction in index.ts

Fixed a bug in the plugin's entry point where an absolute path to the _app file was being incorrectly concatenated with the basePath, resulting in a MODULE_NOT_FOUND error during the file parsing stage.

• Change: Updated the parseFile call to use path.relative(basePath, path.join(pagesPath, app)).

2. Turbopack Compatibility for loadLocaleFrom

Resolved the "Cannot find module as expression is too dynamic" error that occurred when Turbopack encountered the plugin's default import() template for loading locales.

• Detection: Added logic in index.ts to detect if the user's i18n.js configuration includes a custom loadLocaleFrom function.
• Flag Propagation: Introduced a hasLoadLocaleFrom boolean flag passed from the plugin options to the loader and subsequently to all template generators (templateWithHoc, templateWithLoader, templateAppDir).
• Conditional Loading: Modified addLoadLocalesFrom in utils.ts to return an empty loadLocaleFrom definition if the user provides their own, preventing the injection of the problematic dynamic import template.

3. Server-Side Config Access for getT and loadNamespaces

Fixed an issue where server-side functions like getServerSideProps and getStaticProps couldn't access the i18n configuration, causing translation failures in the Pages router.

• Mechanism: Updated templateWithLoader.ts to explicitly set global.i18nConfig before executing the original page loader.
• Result: Ensures that getT and loadNamespaces can retrieve the configuration even when running in the server environment without a request context.

4. Build Process and Parameter Robustness

• Build Script: Updated build-packages.js to use path.join(__dirname, ...) for all filesystem operations, making the build process more robust across different working directories and monorepo structures.
• Default App JS: Fixed the loader.ts to correctly pass the hasLoadLocaleFrom flag to the getDefaultAppJs utility, ensuring the generated _app wrapper respects the custom loader configuration.

Verified Examples

• Example: Basic: Dynamic routes (e.g., /en/more-examples/dynamicroute/example) now correctly load translations via getServerSideProps without crashing.
• Example: Complex: Custom interpolation and nested translation structures function correctly.
• Example: Without-Loader: Manual loadNamespaces calls behave as expected without interfering with the plugin's transformation logic.
• Example: With-App-Directory: Continued support for the App Router with Turbopack.