/**
 * A map for items that are retrieved asynchronously.
 *
 * Its purpose is to avoid retrieving values multiple times in asynchronous settings.
 */
export declare class WaitMap<K, T> extends Map<K, T> {
    private _promises;
    /**
     * Creates a promise for the given key.
     *
     * @param key The key to create a promise for.
     */
    promise(key: K): void;
    /**
     * Returns a boolean indicating whether the given key is in the map or a promise for the key exists.
     *
     * @param key The key to check for.
     */
    has(key: K): boolean;
    /**
     * Sets the value for the given key and resolves the promise for the key if it exists.
     *
     * @param key The key to set the value for.
     * @param value The value to set.
     */
    set(key: K, value: T): this;
    /**
     * Returns a promise that either resolves with the value for the given key or waits for it to be set.
     * If the value is already set, the promise resolves immediately.
     * If the value is not set, the promise resolves when the value is set, provided that the promise has been created.
     *
     * @param key The key to get the value for.
     */
    getOrWait(key: K): Promise<T | undefined>;
}