useMap

Requirements

• Export useMap as a named and default export. Call it only inside a React component or another hook.
• Accept an optional Map or array of key/value pairs; default to an empty Map. Return [map, actions], where actions contains set(key, value), setAll(entries), remove(key), clear(), and reset().
• set adds or replaces an entry. remove deletes a key and safely ignores absent keys. clear removes every entry. setAll replaces all entries with a shallow copy of its input.
• reset restores a shallow snapshot of the initial entries captured on mount. Later initialEntries arguments and external changes to the original Map do not replace that snapshot.
• Use React state so updates become visible on rerender. Do not mutate initial or replacement containers, returned Maps, or Maps captured by an earlier render. Keys and values preserve their references; consumers treat them as read-only.
• Every action in a batched event must take effect in order. Previously saved action functions must operate on the latest state, and each action function must retain a stable identity across rerenders.
• Preserve native Map key equality and insertion ordering. Support arbitrary Map keys and values, including functions as ordinary data; never invoke function-valued entries.
• Keep hook instances independent and support React Strict Mode. Return void from actions. One-shot iterators, deep cloning, reactive mutation of returned Maps, and dynamically replacing the initial entries are outside scope.
• The TypeScript version must support generic key and value types and return a typed tuple. React 19.2.4 is supplied in the sandbox.

Examples

Input: const [map, actions] = useMap([["a", 1]]);
// In an event handler:
actions.set("b", 2);
Output: On the next render: Array.from(map) is [["a", 1], ["b", 2]].

Input: actions.clear();
// After rerender: the Map is empty.
actions.reset();
Output: After the reset rerender: the initial entries are restored.