import { LDLogger } from '@launchdarkly/js-sdk-common';
type FlagChangeKey = `change:${string}`;
/**
 * Type for name of emitted events. 'change' is used for all flag changes. 'change:flag-name-here' is used
 * for specific flag changes.
 */
export type EventName = 'change' | FlagChangeKey | 'dataSourceStatus' | 'error' | 'initialized' | 'ready';
/**
 * Implementation Note: There should not be any default listeners for change events in a client
 * implementation. Default listeners mean a client cannot determine when there are actual
 * application developer provided listeners. If we require default listeners, then we should add
 * a system to allow listeners which have counts independent of the primary listener counts.
 */
export default class LDEmitter {
    private _logger?;
    private _listeners;
    constructor(_logger?: LDLogger | undefined);
    on(name: EventName, listener: Function): void;
    /**
     * Unsubscribe one or all events.
     *
     * @param name
     * @param listener Optional. If unspecified, all listeners for the event will be removed.
     */
    off(name: EventName, listener?: Function): void;
    private _invokeListener;
    emit(name: EventName, ...detail: any[]): void;
    eventNames(): string[];
    listenerCount(name: EventName): number;
}
export {};
//# sourceMappingURL=LDEmitter.d.ts.map