hyperwork-typescriptlisted

# TypeScript **Use:** TypeScript impl tasks. Load with `hyperwork-tdd` skill: `skills: [hyperwork-tdd, hyperwork-typescript]`. ## Toolchain - Test runner: `vitest` preferred; `ts-jest` if repo uses Jest. Check `package.json` scripts first. - Type check: `tsc --noEmit` (never skip — catches type errors tests miss). - Lint: `eslint` + `prettier` per repo config. Run before commit. - `tsconfig.json`: read it. Match `target`, `moduleResolution`, `strict` in new code. ## Patterns - Test file name: `<what>.<condition>.test.ts` or `<what>.spec.ts`. - `describe` / `it` blocks. Name behaviour: `it('returns null when input is empty')`. - Typed mocks: `vi.fn<Args, Return>()` (vitest) or `jest.fn()` typed via generics. - `expect.assertions(N)` in async tests — prevents silent pass on missed await. - Fixtures: typed constants in `__fixtures__/` or co-located `*.fixtures.ts`. ## Do / Don't - DO: run `tsc --noEmit` before declaring green — type errors are bugs. - DO: check `tsconfig.json` paths/aliases before adding imports — broken at emit. - DON'T: use `any` to silence type errors — fix the type. - DON'T: commit with `@ts-ignore` without explaining why. - DON'T: mock modules not at system boundary.