[Marve10s]

Summary:

URLSearchParams.sort() currently uses localeCompare, so query names follow locale collation instead of the UTF-16 code-unit order required by the URL standard. Sorting the same parameters in React Native and a browser can therefore produce different query strings.

For example:

const params = new URLSearchParams('a=first&Z=upper&a=second&z=last&ä=umlaut');
params.sort();
params.toString();

On React Native 0.88.0 and main, this produces a=first&a=second&%C3%A4=umlaut&z=last&Z=upper in an English locale. The expected result is Z=upper&a=first&a=second&z=last&%C3%A4=umlaut.

Compare names directly as strings to use code-unit order, preserve duplicate values, and remove the collation dependency. This also lets the existing Fantom URL test exercise sorting again, which was omitted because its Hermes build lacks ICU collation support.

Changelog:

[GENERAL] [FIXED] - Sort URLSearchParams names in UTF-16 code-unit order instead of locale order.

Test Plan:

Ran the existing URL test file headlessly using the root Jest configuration with a temporary adapter. The adapter selects URL-itest.js and aliases only @react-native/fantom/src/setUpDefaultReactNativeEnvironment to an empty module, retaining Jest's environment setup and the real URL classes.

./node_modules/.bin/jest --config /tmp/rn-url-sort-jest.config.cjs --runInBand --watchman=false --runTestsByPath packages/react-native/Libraries/Blob/__tests__/URL-itest.js

All three tests pass. Against the original implementation, the existing URL test passes and both new sorting regressions fail. They cover mixed-case and accented names, duplicate values, and supplementary characters whose UTF-16 ordering differs from code-point ordering.

./node_modules/.bin/eslint --max-warnings 0 packages/react-native/Libraries/Blob/URLSearchParams.js packages/react-native/Libraries/Blob/__tests__/URL-itest.js
./node_modules/.bin/prettier --check packages/react-native/Libraries/Blob/URLSearchParams.js packages/react-native/Libraries/Blob/__tests__/URL-itest.js
npx --yes --package=flow-bin@0.337.0 flow focus-check --max-workers 2 packages/react-native/Libraries/Blob/URLSearchParams.js packages/react-native/Libraries/Blob/__tests__/URL-itest.js

ESLint, formatting, and focused Flow checking pass. Independent Node probes reproduce the failures on 0.88.0 and main. Substituting the comparator matches native URLSearchParams ordering and still works when localeCompare is forced to throw.

These are headless Node checks. The native Fantom runner, native builds, and full-repository checks were not run.

[meta-codesync]

@javache has imported this pull request. If you are a Meta employee, you can view this in D127563127.

[react-native-bot]

This pull request was successfully merged by @Marve10s in 778fef7

^{When will my fix make it into a release? | How to file a pick request?}

[meta-codesync]

@javache merged this pull request in 778fef7.