Output the files in which a string is found in customValueTemplate

[pxpeterxu]

Why am I submitting this PR

Thanks again for the great framework and maintenance @karellm -- we've now translated our Wanderlog trip planner mobile app to French with help from this!

As a part of the process, we realized that sometimes, translators can benefit with some extra context about the strings they're translating: e.g., it matters if a string like "Round trip" comes from a file called FlightSearchInput.tsx. The customValueTemplates have been really helpful with other annotations, so we thought it'd be helpful to extend it so that we can put:

{
  locales: [SupportedLocale.en],
  output: 'forTranslators.json',
  customValueTemplate: {
    message: '${defaultValue}',
    filePaths: '${filePaths}',
  },
}

Changes

• Add an extra special-case for the customValueTemplate handling (similar to defaultValue) which will also substitute in the paths of all the files where we found a particular key
• Add tests to verify this behavior works properly with multiple files

Note: to make this easier to merge, I also invited you to have write access to our repository.

Example output when run on our codebase:

{
  "Perfect for road trips and saving $$$ on gas! Get the best route auto-rearranged.": {
    "filePaths": [
      "/Users/peter/Code/itineraries/client/templates/LandingPage/LandingPageProFeatureTiles.tsx"
    ]
  },
  "See more": {
    "filePaths": [
      "/Users/peter/Code/itineraries/client/templates/LandingPage/LandingPageReview.tsx",
      "/Users/peter/Code/itineraries/client/templates/LandingPage/LandingPageTestimonial.tsx"
    ]
  }
}

Does it fix an existing ticket?

No

Checklist

• only relevant code is changed (make a diff before you submit the PR)
• tests are included and pass: yarn test (see details here)
• documentation is changed or added

[karellm]

Thanks @pxpeterxu ! This seems like a valuable addition. I will make it to 8.13.0