Function dfs

javascript/0789-minimum-distance-between-two-bst-nodes.js:16–27

(node)

    let [prev, res] = [null, Number.MAX_VALUE];

    function dfs(node) {
        if (node) {
            dfs(node.left);

            if (prev) {
                res = Math.min(res, node.val - prev.val);
            }
            prev = node;

            dfs(node.right);
        }
    }

    dfs(root);