[TIL] leetCode. Merge Two Binary Trees

var mergeTrees = function(root1, root2) {
    let node = new TreeNode()
    if(root1 && root2){
        node.val = root1.val + root2.val;
        node.left = mergeTrees(root1.left, root2.left);
        node.right = mergeTrees(root1.right, root2.right);
        
        return node;
    }else {
        return root1 || root2
    }

};