Fix: warning each child should have a unique key

[ahmadfsalameh]

Checklist

• only relevant code is changed (make a diff before you submit the PR)
• run tests npm run test
• tests are included
• commit message and code follows the Developer's Certification of Origin

@adrai @aiktb @XAOPT When I made the changes in #1813 I wasn't aware of the conditional return, It seems in the example provided here: https://stackblitz.com/edit/vitejs-vite-59g4bx?file=package.json the first if statement in TransWithoutContext is returning void causing the unmodified components (without key) to get rendered.

That function handles both arrays and objects using Object.keys which is smart but also very confusing. We could revert my changes and the warning will disappear but it will cause errors to show up because those components are readonly, also as specified here in your type: https://github.com/i18next/react-i18next/blob/master/TransWithoutContext.d.ts#L16.

In this pull request I'm attempting to solve both issues, mutating the component prop and the keys warning. I split the function into smaller functions which will return a new components value at the end without overriding it.

It might also fix #1733

[coveralls]

coverage: 96.782% (-0.3%) from 97.08%
when pulling 815ff0f on ahmadfsalameh:master
into 37cf812 on i18next:master.

[aiktb]

This looks ok, I tested it locally with the patched code and it successfully fixed the warning.

[aiktb]

Can you add a test for this? @adrai This does not need to be done in this PR
I tried upgrading the react-related development dependencies to 19, which did not break any tests, but some peer dependencies were broken. Upgrading the following dependencies eliminated the peer dependency errors and all tests passed:

npm install @testing-library/react@^16.1.0 @types/react@^19.0.0 react@^19.0.0 react-dom@^19.0.0 react-test-renderer@^19.0.0

- "@testing-library/react": "^16.0.0",
+ "@testing-library/react": "^16.1.0",

- "@types/react": "^18.3",
+ "@types/react": "^19.0.0",

- "react": "^18.3.1",
+ "react": "^19.0.0",

- "react-dom": "^18.3.1",
+ "react-dom": "^19.0.0",

- "react-test-renderer": "^18.3.1",
+ "react-test-renderer": "^19.0.0",

[adrai]

Can you add a test for this? @adrai This does not need to be done in this PR

I tried upgrading the react-related development dependencies to 19, which did not break any tests, but some peer dependencies were broken. Upgrading the following dependencies eliminated the peer dependency errors and all tests passed:

npm install @testing-library/react@^16.1.0 @types/react@^19.0.0 react@^19.0.0 react-dom@^19.0.0 react-test-renderer@^19.0.0

- "@testing-library/react": "^16.0.0",

+ "@testing-library/react": "^16.1.0",



- "@types/react": "^18.3",

+ "@types/react": "^19.0.0",



- "react": "^18.3.1",

+ "react": "^19.0.0",



- "react-dom": "^18.3.1",

+ "react-dom": "^19.0.0",



- "react-test-renderer": "^18.3.1",

+ "react-test-renderer": "^19.0.0",

Can you create a PR for the deps update?

[aiktb]

Can you add a test for this? @adrai This does not need to be done in this PR
I tried upgrading the react-related development dependencies to 19, which did not break any tests, but some peer dependencies were broken. Upgrading the following dependencies eliminated the peer dependency errors and all tests passed:

npm install @testing-library/react@^16.1.0 @types/react@^19.0.0 react@^19.0.0 react-dom@^19.0.0 react-test-renderer@^19.0.0

- "@testing-library/react": "^16.0.0",

+ "@testing-library/react": "^16.1.0",



- "@types/react": "^18.3",

+ "@types/react": "^19.0.0",



- "react": "^18.3.1",

+ "react": "^19.0.0",



- "react-dom": "^18.3.1",

+ "react-dom": "^19.0.0",



- "react-test-renderer": "^18.3.1",

+ "react-test-renderer": "^19.0.0",

Can you create a PR for the deps update?

#1821

[adrai]

Can you add a test for this?

@ahmadfsalameh 👆

[adrai]

merged and released with v15.1.4... please @ahmadfsalameh if possible create a new PR with a dedicated test for this