fix: tree-shaking

[xDivisionByZerox]

Summary

This PR addresses tree-shaking issues by optimizing the handling of locale imports and exports. The changes ensure that only the necessary locale modules are included in the final bundle, enhancing performance and reducing unnecessary file sizes.

This is a major requirement for the release of v9.0.

Details

The previous implementation was causing unnecessary modules to be included during tree-shaking due to the additional export of the implicit allLocales variable.

faker/src/index.ts

Line 39 in 03ac471

export * as allLocales from './locales';

This was refactored into an explicit export under ./locales/index.ts. The generate-locales script has been updated to accommodate this change.

Additionally, the package.json file has been updated to specify "sideEffects": false, which informs bundlers that all files within this package are side-effect-free and can be safely tree-shaken.

To be perfectly honest, even after investigating this issue for multiple hours, I'm still not perfectly sure WHY this exact change fixes the issue.

Please note, that only the combination of these changes will take any action. Applying one or the other change separately does not resolve the issue of everything being included in a final project bundle.

Testing

To verify these changes, follow these steps:

1. Check out this pull request locally.
2. Build the faker library using pnpm run build.
3. Clone our playground repository.
4. Follow the instructions in the README.md file of the playground repository.
5. Override the faker dependency in the playground's package.json (replace "overrides-for-dev" with "overrides-for-dev").
6. Build/compile the playground projects webpack-cjs and webpack-esm.
7. Ensure that the console prints a bundle size number of around 400-480 KB when linking binaries from this pull request branch.
8. Compare this bundle size with the approximately 2.2 MB bundle size when linking binaries from the next branch.

These steps will confirm that the tree-shaking optimizations have reduced the bundle size appropriately and that the library functions as expected with the updated locale handling.

Additional

I consider this a breaking change as of #2335 (comment).

Fixes #1791, #2335.

• Investigate why importing anything from '@faker-js/faker' directly causes all of faker to be bundled. #1791
• Can add sideEffects: false to package.json #2335

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 99.96%. Comparing base (200a38e) to head (4af8837).

Additional details and impacted files

@@           Coverage Diff            @@
##             next    #2790    +/-   ##
========================================
  Coverage   99.95%   99.96%            
========================================
  Files        2971     2971            
  Lines      212553   212696   +143     
  Branches      601      948   +347     
========================================
+ Hits       212467   212611   +144     
+ Misses         86       85     -1     

Files	Coverage Δ
src/index.ts	100.00% <ø> (ø)
src/locales/index.ts	100.00% <100.00%> (ø)

... and 2 files with indirect coverage changes

[ST-DDT]

Awesome, works as expected ❤️

[Shinigami92]

This is so weird ...

Theoretically you changed nothing cause export * from './locale'; in index does the same export for allLocales as before... but it just works magically 🤷

I really don't understand what's going on here

Also I really don't like this sideEffects key, that is undocumented non-standard webpack introduced, but ecosystem accepted. Why is it not e.g. that it needs to be set to sideEffects: true explicitly if you have side effects and the default should be false...

However, great work and don't take my ecosystem-rant personally ❤️

[Shinigami92]

This is not even a breaking change, is it? 👀

Additional

I consider this a breaking change as of #2335 (comment).

Fixes #1791, #2335.

• Investigate why importing anything from '@faker-js/faker' directly causes all of faker to be bundled. #1791
• Can add sideEffects: false to package.json #2335

Ah..., well,
sideEffect is now "okay-ish" as we don't have side effects anymore as historically with the unique method, but this got successfully resolved
Also the investigation is now also not a breaking change anymore ^^'

IMO we can remove the label, but you already also did not add a ! to the PR title, so I'm okay with that

[xDivisionByZerox]

... but you already also did not add a ! to the PR title, so I'm okay with that

Haven't done any actual OSS coding in a while + my work does not use conventional commits (so no ! for breaking changes). So I honestly forgot that this is required ^^

---

I'd still think we should consider this breaking. Just in case. I'll add a migration guide file.

[matthewmayer]

While it's not breaking, it does mean you no longer need to use the workaround to import one locale right? So we could explain that in the migration guide.

[matthewmayer]

Can we also remove the "Individual localized packages" section of the Usage docs if this is no longer needed?

[xDivisionByZerox]

Can we also remove the "Individual localized packages" section of the Usage docs if this is no longer needed?

Wasn't sure about that, but simpl removed it now.

Please check the guide section on the docs preview. I feel like the sections "Custom locales and fallbacks" and "Available lcoales" should be switched now.

[ST-DDT]

Thanks for fixing this. ❤️

[SalahAdDin]

Testing it soon, thanks!

[Shinigami92]

Testing it soon, thanks!

I cant speak for the whole team, but maybe we will do an alpha release today in next 10h 👀 🚀

[ST-DDT]

FFR: #2807

• Release Checklist v9.0.0-alpha.0 #2807