findLargestLevel.js

// helper function to get sum of the level array;
var sumOfLevel = function(levelArray) {
  var sum = levelArray[0];
  for (var i = 1; i < levelArray.length; i++) {
    sum += levelArray[i];
  }
  return sum;
}

var compareSums = function(array) {
  var biggestSum = array[0];
  for (var i = 1; i < array.length; i++) {
    if (biggestSum < array[i]) {
      biggestSum = array[i];
    }
  }
  return biggestSum;
}

var findLargestLevel = function(node) {
  var totalSum = [];
  var firstLevelSum = node.value;
  totalSum.push(firstLevelSum);
  // goal: 1) check if node has children nodes 2) if it has children node, add them into the chlidren array of that level;
  // 1) checking if children nodes are present
  if (node.children.length) {
    var nextLevelChildren = [];
    for (var i = 0; i < node.children.length; i++) {
      // 2) add them into the children array
      nextLevelChildren.push(node.children[i]);
    }
    // 3) getting sum of that level using sumOfLevel (defined above)
    var nextLevelSum = sumOfLevel(nextLevelChildren);
    totalSum.push(nextLevelSum);
    // recurse
    for (var i = 0; i < nextLevelChildren.length; i++) {
      findLargestLevel(nextLevelChildren);
    }
  }
  // compare level's sums 
  return compareSums(totalSum);
}