ESLint quiz

Test your ESLint knowledge with a free interactive quiz — 30 questions with answers and explanations. No signup needed to play.

What makes a rule "type-aware" in @typescript-eslint, as opposed to a plain syntax rule?

1. What makes a rule "type-aware" in @typescript-eslint, as opposed to a plain syntax rule?
2. What key difference distinguishes legacy `.eslintrc.json` config resolution from flat config?
3. What does `eslint --fix` do?
4. What is the effect of listing `js.configs.recommended` before a project-specific rules object in the flat config array?
5. What should generally be the first response when a rule flags code as a violation, before reaching for `eslint-disable`?
6. Can legacy `.eslintrc` format still be used with a recent ESLint version?
7. Given `'no-unused-vars': ['error', { argsIgnorePattern: '^_' }]`, what does the second array element configure?
8. What is "flat config" in ESLint 9+?
9. A config declares `plugins: { react: reactPlugin }` and then sets a rule as `'react/jsx-key': 'error'`. What does the `react/` prefix indicate?
10. A function `saveUser(user)` returns a Promise, but is called without `await` and its result is discarded. Which kind of rule can catch this?
11. Why does linting `.ts`/`.tsx` files require a different parser than ESLint's default?
12. Why are type-aware TypeScript ESLint rules noticeably slower than syntax-only rules?

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