/**
 * Returns the value stored under `key`, inserting and returning `defaultValue`
 * when the key is absent. Mirrors the TC39 `Map.prototype.getOrInsert`
 * proposal.
 *
 * TODO: remove this helper and call `map.getOrInsert(key, defaultValue)`
 * directly once we only target Node 26+ (where the method is built in).
 * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map/getOrInsert
 */
export declare const getOrInsert: <K, V>(map: Map<K, V>, key: K, defaultValue: V) => V;