# Write a Program to Find N-ary Tree Postorder Traversal

# 590. N-ary Tree Postorder Traversal

Given the root of an n-ary tree, return the postorder traversal of its nodes’ values.

Nary-Tree input serialization is represented in their level order traversal. Each group of children is separated by the null value (See examples)

```### Example 1:
```
Input: root = [1,null,3,2,4,null,5,6]
Output: [5,6,3,2,4,1]
```
```
```### Example 2:
```
Input: root = [1,null,2,3,4,5,null,null,6,7,null,8,null,9,10,null,null,11,null,12,null,13,null,null,14]
Output: [2,6,14,11,7,3,12,8,4,13,9,10,5,1]
```
```
```Constraints:
```
The number of nodes in the tree is in the range [0, 104].
0 <= Node.val <= 104
The height of the n-ary tree is less than or equal to 1000.
```
```
```/**
* // Definition for a Node.
* function Node(val,children) {
*    this.val = val;
*    this.children = children;
* };
*/

/**
* @param {Node|null} root
* @return {number[]}
*/
var postorder = function(root) {
const out = [];
const traverse = (node) => {
if (!node) {
return;
}

for (const item of node.children) {
traverse(item);
}
out.push(node.val);

}
traverse(root);
return out;
};
```