[Javascript] - Tail-recursive factorial function

tail-call-optimization.js

// This is just a short reminder of this great explanation:
// http://www.2ality.com/2015/06/tail-call-optimization.html

// not TCO
function factorial(n) {
  if (n <= 0) return 1;
  
  return n * factorial(n-1); // here, the main recursive call not in a tail position because of the `n` context.
}

// TCO
function factorial(n) {
  return recursiveFactorial(n, 1);
}

function recursiveFactorial(n, accumulator) {
  if (n <= 0) return accumulator;

  return recursiveFactorial(n-1, n*accumulator);
}

Legendary

I think you have a bug because of the missing return statement

function factorial(n) {
  return recursiveFactorial(n, 1); // add return here
}

function recursiveFactorial(n, accumulator) {
  if (n <= 0) return accumulator;

  return recursiveFactorial(n-1, n*accumulator);
}

I think you have a bug because of the missing return statement

@gibbok Thanks for your review! I missed that, it's fixed now :)