/**
 * A map with weakly held values (not keys like WeakMap).
 *
 * Local data structure - not a [[Collab]].
 */
export declare class WeakValueMap<K, V extends object> {
    private readonly internalMap;
    private readonly registry?;
    constructor();
    clear(): void;
    delete(key: K): void;
    get(key: K): V | undefined;
    set(key: K, value: V): void;
    [Symbol.iterator](): IterableIterator<[K, V]>;
    /**
     * Check if the key's value no longer exists (has
     * been reclaimed), and if
     * so, delete the key.
     * @param  key [description]
     * @return     [description]
     */
    private checkKey;
}