Frontend and markup
HTML, CSS, JavaScript, TypeScript and React — the parts an interface is built from, one a business owner edits afterwards rather than a developer.
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Easy
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Medium
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Hard
Tests in this topic
6 tests under “Frontend and markup”. Filter by level, or work through them in order.
TypeScript: the type system
Twelve questions about the places where the type system does not behave the way it looks: structural typing and excess properties, narrowing a union, constrained generics, unknown, readonly, utility types, and how satisfies differs from as. Hard level, for people who write TypeScript every day.
- Questions in the test
- 12 questions
- Time limit
- 12 min
Frontend performance and Core Web Vitals
Twelve questions on what LCP, INP and CLS actually measure and which familiar habits break them: the critical rendering path, layout thrashing, lazy loading, fonts, image formats, caching. For people who have already pulled apart more than one slow page.
- Questions in the test
- 12 questions
- Time limit
- 12 min