Sum all integers in a multidimensional array javascript

Question

Let's say I have this:

function arrSum(){
  *code here*
}

How do I write the arrSum function such that it can sum all the integers within a multidimensional array (of variable depth).

I.e.

arrSum([2, 5, [4, 6], 5]) === 22;

I know there must be an answer to this somewhere but I really can't find it. If this is a duplicate please let me know.

Answer 1

Simply you can write a function like this with recursion

function arrSum(arr) {
  var sum = 0;
  // iterate array using forEach, better to use for loop since it have higher performance
  arr.forEach(function(v) {
    // checking array element is an array
    if (typeof v == 'object')
      // if array then getting sum it's element (recursion)
      sum += arrSum(v);
    else
      // else adding the value with sum
      sum += v
  })
  // returning the result
  return sum;
}

console.log(arrSum([2, 5, [4, 6], 5]) === 22);

Using for loop

function arrSum(arr) {
  var sum = 0;
  for (var i = 0; i < arr.length; i++) {
    if (typeof arr[i] == 'object')
      sum += arrSum(arr[i]);
    else
      sum += arr[i];
  }
  return sum;
}

console.log(arrSum([2, 5, [4, 6], 5]) === 22);