How do you deep copy an object in JavaScript?
PICTURE THIS: HOW TO EXPLAIN IT
Simple meaning
StructuredClone is the modern built-in for many values.
WHY — JavaScript instead of guessing?
Why interviewers care about JavaScript:
question about JavaScript.
trade-offs, and what you would actually do on a Frontend project - not buzzwords.
Name the idea, why it exists, then one short example.
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:
- 1StructuredClone is the modern
built-in for many values.
- 2JSON parse stringify is
a common shortcut but drops functions, dates become strings, and undefined keys vanish.
- 3I never pretend spread
is a deep copy.
- 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:
Note: Adapt this scaffold to your own project — keep it under 60–90 seconds.
Key takeaway
StructuredClone is the modern built-in for many values. JSON parse stringify is a common shortcut but drops functions, dates become strings, and undefined keys vanish.