4nm/dist/BackButton/BackButton.js

TypeScript reimplementation of Telegram's official library for communicating with Telegram Web Apps.

import { BACK_BUTTON_PRESSED_EVENT } from '../WebView';
/**
 * This object controls the back button, which can be displayed in the header
 * of the Web App in the Telegram interface.
 * @see https://core.telegram.org/bots/webapps#backbutton
 */
export class BackButton {
    webView;
    webApp;
    _isVisible;
    constructor(webView, webApp, _isVisible = false) {
        this.webView = webView;
        this.webApp = webApp;
        this._isVisible = _isVisible;
    }
    /**
     *
     * @since WebApp version 6.1+
     * @see requireVersion
     * @private
     */
    setVisible(visible) {
        this.webApp.requireVersion('6.1');
        this._isVisible = visible;
        this.webView.postEvent('web_app_setup_back_button', {
            is_visible: visible,
        });
    }
    /**
     * A method to hide the button.
     * @see setVisible
     */
    hide() {
        this.setVisible(false);
    }
    /**
     * Shows whether the button is visible.
     */
    get isVisible() {
        return this._isVisible;
    }
    /**
     * Adds new listener to button click event.
     * @param listener
     */
    onClick(listener) {
        this.webView.on(BACK_BUTTON_PRESSED_EVENT, listener);
    }
    /**
     * Removes listener from button click event.
     * @param listener
     */
    offClick(listener) {
        this.webView.off(BACK_BUTTON_PRESSED_EVENT, listener);
    }
    /**
     * A method to make the button active and visible.
     * @see setVisible
     */
    show() {
        this.setVisible(true);
    }
}