Recursion, while elegant, poses a hidden risk of stack overflow errors in JavaScript due to physical stack space limits. Even logically correct recursive functions can crash when calling themselves too deeply.

Tail call optimization (TCO) offers a theoretical solution by allowing function call frames to be reused, preventing stack growth. However, many JavaScript runtimes, including V8 (used in Chrome, Node.js, and Deno) and SpiderMonkey (Firefox), do not reliably implement TCO. This means tail-recursive code can still lead to stack overflows in production.

Fibonacci, a common recursive example, suffers from both stack depth issues and exponential time complexity. While a tail-recursive version improves time complexity, it doesn't guarantee stack safety due to inconsistent TCO support across JavaScript engines like Safari's JavaScriptCore and Bun. Developers cannot assume TCO will prevent stack overflows.

For production code, especially when input depth is uncertain or user-driven, iterative solutions are generally safer as they don't consume stack frames per step. Alternatively, patterns like trampolining can preserve recursive structure while managing control flow explicitly, avoiding runtime-dependent TCO assumptions. It's advisable to use recursion for small, controlled depths and switch to iteration for potentially deep or unpredictable scenarios.