Flattening a deeply nested Array/Object.

Updated Apr 28, 2026

Short answer

Iterating through elements and recursing if an element is itself a collection.

Deep explanation

Intermediate recursion focuses on optimization and advanced patterns like backtracking. Iterating through elements and recursing if an element is itself a collection.

Real-world example

File system crawlers (scanning directories and sub-directories).

Common mistakes

  • Thinking all recursion is tail-recursive
  • the result must not depend on local calculations after the call.

Follow-up questions

  • Does Python support TCO?

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