// Recursive types (runtime illustration) // Binary tree type Node<T> = { value: T; left?: Node<T>; right?: Node<T> }; const tree: Node<number> = { value: 2, left: { value: 1 }, right: { value: 3 }, }; function preorder<T>(n?: Node<T>, acc: T[] = []): T[] { if (!n) return acc; acc.push(n.value); preorder(n.left, acc); preorder(n.right, acc); return acc; } console.log(preorder(tree).join(" ")); // JSON-like data const jsonLike = { a: 1, b: [true, null], c: { d: "x" } }; console.log(JSON.stringify(jsonLike));