Node Typescript

node-typescript

Produces TypeScript configurations that are explicit, strict, and correct for how the code is consumed. The failures this skill fixes: models copy tsconfigs whose implicit defaults changed between TypeScript majors, pick bundler resolution for unbundled Node packages (broken for consumers), and flip strict mode on a large codebase in one unreviewable big bang.

When NOT to use

• Lint/format rules → node-lint.
• Bundling and exports maps / consumer type resolution → node-packaging (this skill owns declaration emission; the packaging skill owns how consumers resolve it).
• Test runner TS support → node-testing.

Workflow

1. Explicit-config principle first. Never rely on generated or version defaults — TypeScript majors have changed them. Every option that matters is written out, per the blocks in references/tsconfig-playbook.md.
2. Choose by consumption model, not fashion:
   • Published/unbundled Node package → module/moduleResolution in the nodenext family; verbatimModuleSyntax; declaration + declarationMap; isolatedDeclarations where the API surface allows (parallel, tool-agnostic declaration emit).
   • Bundled app code → bundler resolution with noEmit (the bundler emits).
3. Gate it: tsc --noEmit (or -b for project references) as a script and a CI job (wiring → node-ci).
4. Strictification of an existing codebase is a ratchet, not a flip: measure the error surface first, enable flags incrementally (per-flag or per-directory), and keep CI green with a no-new-errors rule. Playbook has the sequence.
5. Verify: clean tsc --noEmit; for published packages, confirm declarations emit and hand consumer-resolution verification to node-packaging's gates.

Output spec

An explicit tsconfig with every load-bearing option stated; type-check script + CI gate; for libraries: declarations emitting with maps; a written rationale for module/resolution choices; strictification plan with measurable checkpoints when applicable.

Gotchas

• bundler resolution on a package consumed by Node directly will typecheck locally and break consumers — the consumption model decides, always.
• verbatimModuleSyntax makes import type mandatory for type-only imports and constrains CJS-emit default exports — enable it with the codemod pass.
• isolatedDeclarations demands explicit return types on exported API — great for libraries, noisy for apps; don't cargo-cult it into app configs.
• TypeScript 7 (the native compiler, GA July 2026) is what typescript@latest installs; explicit tsconfigs stay compatible, but 6.0's deprecations (baseUrl, target: es5, moduleResolution: classic) are hard errors on 7 — the playbook lists them and the @typescript/typescript6 fallback for API-dependent tooling.
• Version-gate: re-verify default/flag behavior against the official TSConfig reference when the TS major changes.

Files

• references/tsconfig-playbook.md — explicit config blocks (library/app), nodenext-vs-bundler decision, strictification ratchet, verification commands.