useTransition for Pending UI (Concurrent Basics)
Keep input responsive by deferring heavy renders with useTransition and show a pending UI while results catch up.
useTransition for Pending UI (Concurrent Basics) is a free React Academy lesson on CoddyKit — lesson 1 of 3. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the React Academy learning path, one of 3 lessons in the course, and your progress syncs across the web and the CoddyKit app.
Concurrent basics
Goal: Keep typing instant while heavy UI updates happen later.
- Mark non-urgent work as a transition
- Show isPending feedback
- Don’t block the main thread with heavy renders
When it helps
Use useTransition when:
- Filtering a long list
- Switching routes/tabs with heavy UI
- Expensive derived views after input
Baseline: no transition (lag)
Without a transition, filtering a big list can feel laggy while React recomputes the UI.
<div id="root"></div>
useTransition: defer heavy work
Wrap the heavy state update in startTransition. Typing stays smooth; isPending shows feedback.
<div id="root"></div>
Urgent vs non-urgent updates
- Urgent: user input, small highlights → update immediately
- Non-urgent: big lists, heavy calculations → wrap in startTransition
- Use isPending for subtle feedback
Tips & gotchas
Notes:
- Transitions don’t make slow code fast; they schedule it better.
- Keep derived work memoized.
- Still profile for real bottlenecks.
useTransition purpose check
Recap
Recap: Separate urgent input from heavy UI updates. Wrap non-urgent work in startTransition and indicate isPending while results update.
Frequently asked questions
Is the “useTransition for Pending UI (Concurrent Basics)” lesson free?
Yes — the full text of “useTransition for Pending UI (Concurrent Basics)” is free to read here on the web, and the React Academy course includes 3 lessons in total. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the React Academy course, upgrade to CoddyKit PRO.
What will I learn in “useTransition for Pending UI (Concurrent Basics)”?
Keep input responsive by deferring heavy renders with useTransition and show a pending UI while results catch up. You practise React Academy with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.
Do I need any experience to start React Academy?
No prior experience is required. React Academy on CoddyKit is structured for beginners through advanced learners; this is — lesson 1 of 3, so you can start here or from the beginning and move at your own pace.
How long does the “useTransition for Pending UI (Concurrent Basics)” lesson take?
Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.
Can I write and run code in this React Academy lesson?
Yes. Every React Academy lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.
All lessons in this course
- useTransition for Pending UI (Concurrent Basics)
- Suspense for Async Boundaries (Concepts)
- Fallbacks & Splitting Slow Paths