The **tree‑selector** package lets you apply CSS‑style selectors to any hierarchical JavaScript object, not just the DOM. By supplying a set of lookup functions (e.g., how to get a node’s tag, id, class, children, attributes, etc.), it builds `querySelector` and `matches` utilities that can query or test nodes with full selector syntax—including attribute selectors, pseudo‑classes like `:first‑child`, `:contains()`, and sibling combinators. It’s aimed at developers who need a flexible, selector‑based way to search custom tree‑like data structures (e.g., virtual DOMs, ASTs, or other nested object models).