JS fast and simple solution
\n\njs\nvar rangeSumBST = function(root, L, R) {\n    if(!root)return 0  \n    let v = (root.val <= R && root.val >= L)? root.val : 0\n    return v + rangeSumBS
\n\n```js\nvar rangeSumBST = function(root, L, R) {\n    if(!root)return 0  \n    let v = (root.val <= R && root.val >= L)? root.val : 0\n    return v + rangeSumBST(root.left, L, R) + rangeSumBST(root.right, L, R)\n};\n```
['Recursion', 'JavaScript']