What is the difference between slice and splice?
PICTURE THIS: ARRAY IN MEMORY
Index starts at 0. Scan once for max — O(n).
Simple meaning
Slice returns a shallow copy of a portion and does not change the original, which is what I want in React.
WHY — JavaScript instead of guessing?
Why interviewers care about JavaScript:
contrast on JavaScript, not two memorised paragraphs.
the developer, then one case where picking wrong hurts.
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:
- 1Slice returns a shallow
copy of a portion and does not change the original, which is what I want in React.
- 2Splice mutates the array
by deleting or inserting in place.
- 3Mutating state arrays is
a classic interview red flag.
- 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
Slice returns a shallow copy of a portion and does not change the original, which is what I want in React. Splice mutates the array by deleting or inserting in place.