Learnt from: FatahChan
Repo: TanStack/router PR: 5475
File: e2e/react-start/basic-prerendering/src/routes/redirect/$target/via-beforeLoad.tsx:8-0
Timestamp: 2025-10-14T18:59:33.990Z
Learning: In TanStack Router e2e test files, when a route parameter is validated at the route level (e.g., using zod in validateSearch or param validation), switch statements on that parameter do not require a default case, as the validation ensures only expected values will reach the switch.

Learnt from: nlynzaad
Repo: TanStack/router PR: 5182
File: e2e/react-router/basic-file-based/src/routes/non-nested/named/$baz_.bar.tsx:3-5
Timestamp: 2025-09-22T00:56:49.237Z
Learning: In TanStack Router, underscores are intentionally stripped from route segments (e.g., `$baz_` becomes `baz` in generated types) but should be preserved in base path segments. This is the correct behavior as of the fix in PR #5182.

Learnt from: nlynzaad
Repo: TanStack/router PR: 5182
File: e2e/react-router/basic-file-based/tests/non-nested-paths.spec.ts:167-172
Timestamp: 2025-09-22T00:56:53.426Z
Learning: In TanStack Router, underscores are intentionally stripped from route segments during path parsing, but preserved in base path segments. This is the expected behavior implemented in PR #5182.

Learnt from: nlynzaad
Repo: TanStack/router PR: 5402
File: packages/router-generator/tests/generator/no-formatted-route-tree/routeTree.nonnested.snapshot.ts:19-21
Timestamp: 2025-10-08T08:11:47.088Z
Learning: Test snapshot files in the router-generator tests directory (e.g., files matching the pattern `packages/router-generator/tests/generator/**/routeTree*.snapshot.ts` or `routeTree*.snapshot.js`) should not be modified or have issues flagged, as they are fixtures used to verify the generator's output and are intentionally preserved as-is.

Learnt from: nlynzaad
Repo: TanStack/router PR: 5284
File: e2e/react-start/basic/server.js:50-0
Timestamp: 2025-09-28T21:41:45.233Z
Learning: In Express v5, catch-all routes must use named wildcards. Use `/*splat` to match everything except root path, or `/{*splat}` (with braces) to match including root path. The old `*` syntax is not allowed and will cause "Missing parameter name" errors. This breaking change requires explicit naming of wildcard parameters.

Learnt from: nlynzaad
Repo: TanStack/router PR: 5732
File: packages/start-client-core/src/client/hydrateStart.ts:6-9
Timestamp: 2025-11-02T16:16:24.898Z
Learning: In packages/start-client-core/src/client/hydrateStart.ts, the `import/no-duplicates` ESLint disable is necessary for imports from `#tanstack-router-entry` and `#tanstack-start-entry` because both aliases resolve to the same placeholder file (`fake-start-entry.js`) in package.json during static analysis, even though they resolve to different files at runtime.