1class TreeNode {
2    constructor(val, left = null, right = null) {
3        this.val = val;
4        this.left = left;
5        this.right = right;
6    }
7}
8
9function averageOfLevels(root) {
10    const averages = [];
11    const queue = [root];
12    while (queue.length > 0) {
13        const count = queue.length;
14        let sum = 0;
15        for (let i = 0; i < count; i++) {
16            const node = queue.shift();
17            sum += node.val;
18            if (node.left) queue.push(node.left);
19            if (node.right) queue.push(node.right);
20        }
21        averages.push(sum / count);
22    }
23    return averages;
24}
25
26// Example usage
27const a = new TreeNode(3);
28const b = new TreeNode(9);
29const c = new TreeNode(20);
30const d = new TreeNode(15);
31const e = new TreeNode(7);
32
33a.left = b;
34a.right = c;
35c.left = d;
36c.right = e;
37
38console.log(averageOfLevels(a));