/**
 * Base Registry
 *
 * Generic base class for all FlowDrop registries. Provides the shared
 * mechanics: Map storage, subscribe/notify, onClear callbacks, and size tracking.
 *
 * Subclasses define their own `register()` method with domain-appropriate
 * signatures, using `this.items` and `this.notifyListeners()` directly.
 *
 * @example
 * ```typescript
 * class MyRegistry extends BaseRegistry<string, MyItem> {
 *   register(item: MyItem, overwrite = false): void {
 *     if (this.items.has(item.id) && !overwrite) {
 *       throw new Error(`Already registered: ${item.id}`);
 *     }
 *     this.items.set(item.id, item);
 *     this.notifyListeners();
 *   }
 * }
 * ```
 */
export declare class BaseRegistry<K, V> {
    /** Internal storage map */
    protected items: Map<K, V>;
    /** Change listeners */
    private listeners;
    /** Callbacks invoked when the registry is cleared (for resetting flags) */
    private clearCallbacks;
    /**
     * Unregister an item by key.
     *
     * @param key - The key to remove
     * @returns true if the key was found and removed, false otherwise
     */
    unregister(key: K): boolean;
    /**
     * Get an item by key.
     *
     * @param key - The key to look up
     * @returns The item if found, undefined otherwise
     */
    get(key: K): V | undefined;
    /**
     * Check if a key is registered.
     *
     * @param key - The key to check
     * @returns true if the key is registered
     */
    has(key: K): boolean;
    /**
     * Get all registered keys.
     *
     * @returns Array of registered keys
     */
    getKeys(): K[];
    /**
     * Get all registered values.
     *
     * @returns Array of all registered items
     */
    getAll(): V[];
    /**
     * Subscribe to registry changes.
     * Called whenever items are registered, unregistered, or cleared.
     *
     * @param listener - Callback to invoke on changes
     * @returns Unsubscribe function
     */
    subscribe(listener: () => void): () => void;
    /**
     * Register a callback invoked when the registry is cleared.
     * Useful for resetting module-level registration flags in tests.
     *
     * @param callback - Function to call on clear
     * @returns Unsubscribe function
     */
    onClear(callback: () => void): () => void;
    /**
     * Clear all registrations.
     * Invokes onClear callbacks first, then notifies listeners.
     */
    clear(): void;
    /**
     * Get the count of registered items.
     */
    get size(): number;
    /**
     * Notify all change listeners.
     */
    protected notifyListeners(): void;
}