What is code splitting in a SPA?
PICTURE THIS: REACT RENDER CYCLE
State changesetState / hook
ReconcileVirtual DOM diff
CommitUpdate real DOM
Simple meaning
Loading route or feature bundles on demand.
WHY — Performance instead of guessing?
Why interviewers care about Performance:
Performance questions separate people
who only read docs from people who shipped.
Keep it short, concrete,
and tied to Frontend work.
Stay structured
Name the idea, why it exists, then one short example.
Close cleanly
End with when you use it and one common pitfall.
STEPS — What happens step by step?
Before you speak the answer, walk the interviewer through these steps:
- 1Loading route or feature
bundles on demand.
- 2Why it exists
Reduces initial JS.
- 3React.lazy and dynamic import
are common tools.
- 4Give an example
One tiny concrete case you can say aloud.
- 5Common mistake
What juniors usually get wrong.
- 6Close
When you pick this over the alternative.
EXAMPLE — See it in action
Here's a short line you can speak, broken into clear beats:
Say this line
“Reduces initial JS.”
Break into beats
ReducesinitialJS
Speaking order
29874083374
Note: Adapt this scaffold to your own project — keep it under 60–90 seconds.
Key takeaway
Loading route or feature bundles on demand. Reduces initial JS.