Function dfs

javascript/1325-delete-leaves-with-a-given-value.js:18–26

(node)

 */
var removeLeafNodes = function (root, target) {
    const dfs = (node) => {
        if (!node) return null;
        node.left = dfs(node.left);
        node.right = dfs(node.right);
        if (!node.left && !node.right) {
            if (node.val === target) return null;
        }
        return node;
    };

    return dfs(root);
};