Easy Performance Question 47 of 229

What is code splitting?

Frontend Master · Speak this in 60–90 seconds · Faridabad & Delhi NCR

PICTURE THIS: REACT RENDER CYCLE

State changesetState / hook

ReconcileVirtual DOM diff

CommitUpdate real DOM

Simple meaning

Code splitting breaks the JS bundle so the first paint only downloads the route the user opened.

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:

1
Code splitting breaks the
JS bundle so the first paint only downloads the route the user opened.
2
React.lazy, dynamic import, and
Next.js pages all do this.
3
The tradeoff is a
loading state for that chunk, which I plan with a Suspense fallback.
4
Give an example
One tiny concrete case you can say aloud.
5
Common mistake
What juniors usually get wrong.
6
Close
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

“React.lazy, dynamic import, and Next.js pages all do this.”

Break into beats

ReactlazydynamicimportandNext

Speaking order

2987408337471632900

Note: Adapt this scaffold to your own project — keep it under 60–90 seconds.

Key takeaway

Code splitting breaks the JS bundle so the first paint only downloads the route the user opened. React.lazy, dynamic import, and Next.js pages all do this.