/**
 * Gets existing value from Map or lazily creates it if missing.
 *
 * Implements the lazy initialization pattern: returns existing value if key
 * exists, otherwise calls generator function to create new value, stores it,
 * and returns it. Ensures generator is only called when necessary, avoiding
 * wasteful computation.
 *
 * Used throughout AutoBE for caching event listeners, validation state, and
 * other expensive-to-create objects that should be initialized on first
 * access.
 *
 * @param dict Map to query and potentially update
 * @param key Key to look up or create
 * @param generator Function to create value if key doesn't exist
 * @returns Existing or newly created value
 */
export declare function emplaceMap<Key, T>(dict: Map<Key, T>, key: Key, generator: () => T): T;