What is a base case in recursion, and what happens if you omit it?
PICTURE THIS: JAVASCRIPT EVENT LOOP
Simple meaning
The base case is the input that returns immediately without another recursive call, such as n == 0 for factorial.
WHY — Recursion instead of guessing?
Why interviewers care about Recursion:
who only read docs from people who shipped.
and tied to DSA work.
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:
- 1The base case is
the input that returns immediately without another recursive call, such as n == 0 for factorial.
- 2Without it the call
stack grows until a stack overflow.
- 3Every recursive solution should
name the base case, the recursive case, and the O(depth) stack cost.
- 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
The base case is the input that returns immediately without another recursive call, such as n == 0 for factorial. Without it the call stack grows until a stack overflow.