Closes #1104

Blockers / TODO

• Address TS linting errors

Changes

• Upgrade to React v19
  • Update imports
  • Remove usage of defaultProps
• Fix E2E tests that reference recently updated CFGov content
• Upgrade and integrate design-system-react

Notes

• I have reviewed snapshot test failures and they seem to be acceptable
  • Fixed: <FormButtonGroup/> missing flex class that was causing unexpected spacing issue. I accidentally removed it during this upgrade and snapshot testing caught it!
  • Reviewed: Snapshots are out of date with logic showing/hiding of navbar based on user being signed-in/out
  • Reviewed: USA flag sometimes renders in snapshots as blurry but looks clear in the actual app
  • Reviewed: Field level alert content now wraps differently due to 670px width restriction

Next steps

• Check-in with other teams using design-system-react to see if they can also upgrade to React v19 (the DSR upgrade is not backwards compatible). If they can't, we can move forward by continuing to maintain and utilize the DSR's upgrade-to-react-19 branch.

How to test this PR

1. yarn && yarn test:e2e --headless

Steps taken to upgrade to React v19

1. npx react-codemod update-react-imports
   1. Error: did not recognize object of type "TSSatisfiesExpression" while attempting to process the following files, but none seem to have any codemods that need to be applied.
   • src/api/requests/submitUserProfileFi.ts
   • src/api/requests/submitUpdateFinancialProfile.ts
   • src/components/CommonLinks.tsx
2. yarn add --exact react@^19.0.0 react-dom@^19.0.0
3. yarn add --exact @types/react@^19.0.0 @types/react-dom@^19.0.0
   • If the above fails to update versions, manually update package.json
4. npx codemod@latest react/19/migration-recipe
   • No changes
5. npx types-react-codemod@latest preset-19 ./
   • Lots of updates to import type JSX
   • Our linter automatically removes these updates as "unecessary" ex. ReactElement<any> => ReactElement
6. Manually applied: useRef requires an argument
   1. https://react.dev/blog/2024/04/25/react-19-upgrade-guide#useref-requires-argument
7. Remove deprecated usage of FunctionalComponent.defaultProps
   • https://react.dev/blog/2024/04/25/react-19-upgrade-guide#removed-deprecated-react-apis
   • Note: Codemods did not catch this in our code so I had to manually remove these. I recommend to search for defaultProps and evaluate/update.
8. Upgrade DSR to React v19 and Storybook v8