TypeScript review reference

To catch TypeScript type-safety issues that pass compilation, review diffs for unsafe `as` assertions, `any` vs `unknown` drift, and missing exhaustiveness checks in discriminated unions. Targeting these anti-patterns prevents runtime errors that strict mode and common linters miss.

During a TypeScript 5.x code review, look for misuse of `satisfies`, `const` type parameters, `NoInfer`, and Stage 3 decorators. Also check for structural ID collisions, shallow `Readonly` assumptions, and boundary validation gaps that compromise type safety.

Review a PR for unsafe type assertions and missing narrowing by applying a targeted checklist to modified `*.ts` or `*.tsx` files. Flag risky `as` casts, `null`/`undefined` drift, and missing literal preservation to ensure safe remediation patterns.

Yes, this TypeScript review approach works with `tsconfig.json` changes. It applies to PRs modifying TypeScript source files or tsconfig settings, evaluating boundary validation and literal preservation impacts on type system strictness.

TypeScript code compiles clean but still has footguns because strictness settings and linters miss boundary validation gaps, unsafe casts, and shallow `Readonly` assumptions. Modern TS 5.x constructs like `satisfies` require targeted detection signals to remediate.

Check for exhaustiveness in TypeScript discriminated unions whenever code modifies boundary validations or handles multiple union variants. Missing exhaustiveness checks allow unhandled cases to pass compilation while remaining error-prone during real execution.