What is recursion?

Recursion is a function that calls itself during execution.

Two main components of a recursive function:

• Base case (or exit condition): The condition under which recursion terminates. Without it, the function will call itself infinitely, leading to a stack overflow.
• Recursive step: The step where the function calls itself with a modified argument, bringing it closer to the base case.

Example of calculating factorial using recursion:

function factorial(n) {
  // Base case
  if (n <= 1) {
    return 1;
  }
  // Recursive step
  return n * factorial(n - 1);
}

// usage
// console.log(factorial(5)); // Output: 120

Advantages of recursion:

• Can make code more readable and elegant for certain tasks (e.g., tree traversal, fractal processing).
• Well-suited for problems that naturally formulate in terms of smaller subproblems of the same type.

Disadvantages of recursion:

• Can be less efficient compared to iterative solutions due to overhead of function calls and stack management.
• Incorrectly implemented base case can lead to infinite recursion and stack overflow.
• Sometimes harder to debug.

In Node.js, as in other languages, deep recursion should be used cautiously due to stack size limitations. For deep recursive structures, tail recursion optimization can be applied if supported by the engine (although V8 does not optimize all tail recursion cases automatically), or the recursive call can be transformed into an iterative one.