Function sumArrayWDefault

w3/d2/sum-array.js:43–50

(arr, sum = 0)

function sumArrayWDefault(arr, sum = 0) {
  if(!arr.length) return sum;

  let shifted = arr.shift();
  sum += shifted;

  return sumArrayWDefault(arr, sum);
}

/*
sumArrayWDefault([], 6)     => 6