/** @packageDocumentation
 * @module Collections
 */
import { BeEvent } from "./BeEvent";
/** A standard [Map<K,V>](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map) that emits an event when its contents change.
 * @public
 */
export declare class ObservableMap<K, V> extends Map<K, V> {
    /** @internal */
    get [Symbol.toStringTag](): string;
    /** Emitted after any change to the contents of this map. */
    readonly onChanged: BeEvent<() => void>;
    /** Construct a new ObservableMap.
     * @param elements Optional elements with which to populate the new map.
     */
    constructor(elements?: Iterable<readonly [K, V]> | undefined);
    /** Invokes [Map.set](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map/set), raising
     * the [[onChanged]] event unless `key` is already present with the same `value`.
     */
    set(key: K, value: V): this;
    /** Invokes [Map.delete](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map/delete), raising
     * the [[onChanged]] event if the key was removed from the map.
     */
    delete(key: K): boolean;
    /** If this map is not already empty, invokes [Map.clear](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map/clear)
     * and raises the [[onChanged]] event.
     */
    clear(): void;
    /** Add or update multiple entries in the map, raising [[onChanged]] only once after all items are set, if the contents of
     * the map changed as a result.
     * This is more efficient than calling [[set]] in a loop when listeners need not be notified of each individual change.
     * @param items The entries to add or update.
     */
    setAll(items: Iterable<readonly [K, V]>): void;
    /** Delete multiple keys from the map, raising [[onChanged]] only once after all keys are deleted.
     * This is more efficient than calling [[delete]] in a loop when listeners need not be notified of each individual deletion.
     * @param keys The keys to delete.
     * @returns The number of keys that were actually deleted (i.e., were present in the map).
     */
    deleteAll(keys: Iterable<K>): number;
}
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