export interface EmulatorEnv {
    FIREBASE_AUTH_EMULATOR_HOST: string | undefined;
}
export declare function emulatorHost(env?: EmulatorEnv): string | undefined;
/**
 * When true the SDK should communicate with the Auth Emulator for all API
 * calls and also produce unsigned tokens.
 */
export declare const useEmulator: (env?: EmulatorEnv) => boolean;