TypeScript Code Quality
& Strict Mode Enforcement

// tsconfig.json
{ "compilerOptions": { "strict": false } }

Fix: Remove strict: false to re-enable all strict type checks

const cost = parseFloat(req.body.amount);
this.subtotal = parseFloat(rawAmount);

Fix: Use Decimal or Big for financial calculations — IEEE-754 float loses cents at scale

users.forEach(async (user) => {
  await sendEmail(user.email);
});

Fix: await Promise.all(users.map(async (user) => sendEmail(user.email)))

// @ts-ignore
const result = dangerousFunction();

Fix: Add explanation: // @ts-ignore: dangerousFunction is untyped — fix in #1234

How does GateTest enforce TypeScript strict mode?

GateTest's typescriptStrictness module walks every tsconfig.json in your project (including JSONC with // comments, tsconfig.app.json, tsconfig.node.json). It flags strict: false (error — disables all strict checks at once), noImplicitAny: false (error — allows untyped code), skipLibCheck: true (warning — hides type errors in dependencies), strictNullChecks: false (warning — allows null/undefined anywhere), and strictFunctionTypes: false (warning — breaks function parameter type safety).

Can GateTest detect @ts-ignore abuse?

Yes. The typescriptStrictness module flags @ts-nocheck at the file level (error — suppresses all type checking in that file) and @ts-ignore / @ts-expect-error annotations that have no explanatory comment on the same line (warning — a reason-less suppress is a ticking time bomb). Test files (*.test.ts, *.spec.ts) and declaration files (*.d.ts) are exempt — these legitimately need type flexibility.

Does GateTest find unused TypeScript exports?

Yes. The deadCode module detects exported symbols that nothing in the codebase imports, files that nothing imports, and commented-out code blocks of 10+ lines. It understands Next.js App Router conventions so page.tsx, layout.tsx, and route.ts exports are never false-positively flagged.

How does GateTest detect circular imports in TypeScript projects?

The importCycle module builds a dependency graph from your .ts and .tsx files — resolving relative specifiers through extension fallback and ./x/index.ts lookup. It uses Tarjan's strongly-connected-component algorithm to find every cycle of 2+ files. Type-only imports (import type, export type) are correctly excluded — they're erased at build time and can't cause runtime TDZ errors.

Does GateTest catch async/await mistakes in TypeScript?

Several modules cover this. asyncIteration catches .forEach(async ...) (warning — forEach doesn't await), .filter(async ...) (error — Promise is always truthy, predicate is meaningless), .reduce(async ...) (error — accumulator becomes a Promise chain), and .map(async ...) not wrapped in Promise.all (warning — unwrapped Promise array). errorSwallow catches fire-and-forget .save()/.send()/.commit() calls without await or .catch().

Does GateTest detect money/float precision bugs in TypeScript?

Yes. The moneyFloat module flags money-named variables (price, total, amount, tax, fee, subtotal, balance, and currency codes usd/eur/gbp/etc.) assigned from parseFloat() or Number() — both are IEEE-754 floating-point and will accumulate rounding errors in financial calculations. Safe if your file imports decimal.js, big.js, bignumber.js, or dinero.js.