Closure CavesISSUE #8 of 61

recursion · function calls itself

LambdaVSThe Mutator

Lambda saysRecursion is a function calling itself — with a base case that stops it.

A recursive function solves a problem by calling itself on a smaller piece, until a base case ends the chain. It's natural for trees, nested structures, and divide-and-conquer. Always have a reachable base case or you'll blow the call stack ("Maximum call stack size exceeded").

Power-ups you unlock

Function calls itself on a smaller input
A base case stops the recursion
Natural for trees and nested data
Missing base case → stack overflow

The Mutator attacks — common mistakes

No base case → infinite recursion
Base case never reached for some inputs
Deep recursion overflowing the stack (use iteration)

Boss battleWrite a recursive factorial with a base case at n <= 1.

Example code

<!doctype html><html><head><meta charset="utf-8"></head>
<body style="background:#06040d;color:#e6e0ff;font-family:monospace;padding:20px"><pre id="o"></pre>
<script>function fact(n){ return n<=1 ? 1 : n*fact(n-1); }
document.getElementById('o').textContent='5! = '+fact(5);</script></body></html>

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