How to get sum of children and check if it’s equal to root in Javascript?

Let us consider Parent node is root node, and children nodes are left node and a right node.
⦁ root.left points to a node left
⦁ root.right points to a node right.
Inside checkTree function you receive root as a parameter. This root is a instance of TreeNode which will look something like right and left can point to other TreeNodes as well.

Scenario 1:
So suppose if tree is something like this

root is 9, root.left would be node 4 and root.right would be node 5

root.left.val is equal to 4 and root.right.val is equal to 5 & root.val is 9

So if addition of both root.left.val & root.right.val is equal to root.val the return statement would return true else false.

So in this case it would return true as 4 + 5 is equals to 9

var checkTree = function(root) {
return root.left.val + root.right.val === root.val
};

Scenario 2:
So suppose if tree is something like this

// Definition for a binary tree node. 
function TreeNode(val, left, right) {
this.val = (val===undefined ? 0 : val) 
this.left = (left===undefined ? null : left) 
this.right = (right===undefined ? null : right)
}

root is 5, root.left would be node 1 and root.right would be node 3 root.left.val is equal to 1 and root.right.val is equal to 3 & root.val is 5
So if addition of both root.left.val & root.right.val is equal to root.val the return statement would return true else false.

So in this case it would return false as 1 + 3 is not equal to 5.

var checkTree = function(root) {
return root.left.val + root.right.val === root.val
};