Practice React Coding Challenges to Pass Your Interview
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Overview
Learn the difference between useState and useRef by creating two counters and observing how state and refs affect component rendering.
Requirements
- Create two counters: counter state and counter ref, each with increment and decrement buttons.
- The counter state should update and reflect its value in the UI when incremented or decremented.
- The counter ref should update its value when incremented or decremented without triggering a UI update.
- After triggering a rerender with the counter state, the counter ref should show its updated value.
Notes
- Understand the difference between
useStateanduseRefin React. - Learn how
useRefcan store mutable values without causing rerenders. - Practice triggering and observing rerenders with
useState. - Gain clarity on when to use
useStatevsuseRefdepending on UI updates.
Tests
- increment state value on plus button click
- decrement state value on minus button click
- does not update ref value in DOM without re-render
- displays updated ref value after state re-render
Last challenges
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Build an infinite scroll list using the Intersection Observer API — fetch the next page of Rick & Morty characters automatically as the sentinel element enters the viewport.
ddduseStateuseEffectfetchingIntersectionObserver
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