Average of Levels in Binary Tree

import { TreeNode } from '@algorithm/lib';
 
export function averageOfLevels(root: TreeNode | null): number[] {
  if (!root) {
    return [];
  }
 
  const answer: number[] = [];
  let currentNodes = [root];
 
  while (0 < currentNodes.length) {
    let totalValue = 0;
    const totalLength = currentNodes.length;
    const nextNodes: TreeNode[] = [];
 
    currentNodes.forEach((currentNode) => {
      if (currentNode.left) {
        nextNodes.push(currentNode.left);
      }
      if (currentNode.right) {
        nextNodes.push(currentNode.right);
      }
      totalValue += currentNode.val;
    });
 
    answer.push(totalValue / totalLength);
    currentNodes = nextNodes;
  }
 
  return answer;
}