Detect reused keys

[andrewRichardson]

Why am I submitting this PR

Allow detect key reuse and option to warn or fail on reuse. Example: dev writes t('foobar') in two different files ultimately writing translations to the same JSON. With config warnOnDuplicates: true, parser now warns appropriately, and counts the number of warnings like so: . Warnings: XXX warnings encountered to give a general idea of the number of reused keys. With config failOnWarnings, this situation would cause an exit 1.

Does it fix an existing ticket?

Yes #495

Checklist

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

[andrewRichardson]

@karellm

[andrewRichardson]

@karellm Thanks for the PR, it looks good! I've added couple comments. My main concern is that tests are a bit light.

I addressed your concerns including adding stronger tests. Let me know if you have any other concerns! Thanks.

[andrewRichardson]

@karellm bump

[amandapouget]

This feature seems really cool! Can we get to merge on it?

[andrewRichardson]

@karellm bump x2

[Laityned]

rebase from main to run all tests instead of a single test + coverage

[andrewRichardson]

@karellm bump x3

[andrewRichardson]

@karellm bump x4?