import { EventListener } from '@telegram-apps/bridge';
/**
 * Signal indicating if the Back Button is currently visible.
 */
export declare const _isVisible: import('@telegram-apps/signals').Signal<boolean>, isVisible: import('@telegram-apps/signals').Computed<boolean>;
/**
 * Signal indicating if the Back Button is currently mounted.
 */
export declare const _isMounted: import('@telegram-apps/signals').Signal<boolean>, isMounted: import('@telegram-apps/signals').Computed<boolean>;
/**
 * Signal indicating if the Back Button is supported.
 */
export declare const isSupported: import('@telegram-apps/signals').Computed<boolean>;
/**
 * Hides the Back Button.
 * @param
 * @throws {FunctionNotAvailableError} The environment is unknown
 * @throws {FunctionNotAvailableError} The SDK is not initialized
 * @throws {FunctionNotAvailableError} The function is not supported
 * @throws {FunctionNotAvailableError} The parent component is not mounted
 * @since Mini Apps v6.1
 * @example
 * if (hide.isAvailable()) {
 *   hide();
 * }
 */
export declare const hide: import('../../wrappers/wrapSafe.js').SafeWrapped<() => void, true, never>;
/**
 * Mounts the Back Button restoring its state.
 * @param
 * @throws {FunctionNotAvailableError} The environment is unknown
 * @throws {FunctionNotAvailableError} The SDK is not initialized
 * @throws {FunctionNotAvailableError} The function is not supported
 * @since Mini Apps v6.1
 * @example
 * if (mount.isAvailable()) {
 *   mount();
 * }
 */
export declare const mount: import('../../wrappers/wrapSafe.js').SafeWrapped<() => void, true, never>;
/**
 * Adds a new Back Button click listener.
 * @param fn - event listener.
 * @returns A function to remove bound listener.
 * @throws {FunctionNotAvailableError} The environment is unknown
 * @throws {FunctionNotAvailableError} The SDK is not initialized
 * @throws {FunctionNotAvailableError} The function is not supported
 * @since Mini Apps v6.1
 * @example
 * if (onClick.isAvailable()) {
 *   const off = onClick(() => {
 *     console.log('User clicked the Back Button');
 *     off();
 *   });
 * }
 */
export declare const onClick: import('../../wrappers/wrapSafe.js').SafeWrapped<(fn: EventListener<"back_button_pressed">) => VoidFunction, true, never>;
/**
 * Removes the Back Button click listener.
 * @param fn - an event listener.
 * @throws {FunctionNotAvailableError} The environment is unknown
 * @throws {FunctionNotAvailableError} The SDK is not initialized
 * @throws {FunctionNotAvailableError} The function is not supported
 * @since Mini Apps v6.1
 * @example
 * if (offClick.isAvailable()) {
 *   function listener() {
 *     console.log('User clicked the Back Button');
 *     offClick(listener);
 *   }
 *   onClick(listener);
 * }
 */
export declare const offClick: import('../../wrappers/wrapSafe.js').SafeWrapped<(fn: EventListener<"back_button_pressed">) => void, true, never>;
/**
 * Shows the Back Button.
 * @throws {FunctionNotAvailableError} The environment is unknown
 * @throws {FunctionNotAvailableError} The SDK is not initialized
 * @throws {FunctionNotAvailableError} The function is not supported
 * @throws {FunctionNotAvailableError} The parent component is not mounted
 * @since Mini Apps v6.1
 * @example
 * if (show.isAvailable()) {
 *   show();
 * }
 */
export declare const show: import('../../wrappers/wrapSafe.js').SafeWrapped<() => void, true, never>;
/**
 * Unmounts the Back Button.
 *
 * Note that this function does not remove listeners added via the `onClick`
 * function, so you have to remove them on your own.
 * @see onClick
 */
export declare function unmount(): void;