Boilerplate Extension for creating new widget plugin for elementor

elementor-widget-extension.php

<?php
/*
Plugin Name: Timer element for elementor
Plugin URI: https://devrupash.com
Description: Timer element for elementor
Version: 1.0
Author: Rupash Das
Author URI: https://devrupash.com
License: GPLV2 or later
Text Domain: timerelement
Domain Path: /Languages/
 */
if ( !defined( 'ABSPATH' ) ) {
    die( __( "Direct Access is not allowd", "timerelement" ) );
}

final class TimerElementExtension {

    const VERSION = '1.0';
    const MINIMUM_ELEMENTOR_VERSION = '2.0.0';
    const MINIMUM_PHP_VERSION = '5.4';

    private static $_instance = null;
    public static function instance() {

        if ( is_null( self::$_instance ) ) {
            self::$_instance = new self();
        }
        return self::$_instance;

    }
    public function __construct() {
        add_action( 'plugins_loaded', [$this, 'init'] );
    }
    public function init() {
        load_plugin_textdomain( 'timerelement' );

        // Check if Elementor installed and activated
        if ( !did_action( 'elementor/loaded' ) ) {
            add_action( 'admin_notices', [$this, 'admin_notice_missing_main_plugin'] );
            return;
        }

        // Check for required Elementor version
		if ( ! version_compare( ELEMENTOR_VERSION, self::MINIMUM_ELEMENTOR_VERSION, '>=' ) ) {
			add_action( 'admin_notices', [ $this, 'admin_notice_minimum_elementor_version' ] );
			return;
        }
        
        // Check for required PHP version
		if ( version_compare( PHP_VERSION, self::MINIMUM_PHP_VERSION, '<' ) ) {
			add_action( 'admin_notices', [ $this, 'admin_notice_minimum_php_version' ] );
			return;
        }

        // Add Plugin actions
        add_action( 'elementor/widgets/widgets_registered', [ $this, 'init_widgets' ] );

        
        //hook for enqueue CSS in elementor frontend mode
        add_action("elementor/frontend/after_enqueue_styles", [$this, 'widget_styles']);

        //hook for enqueue js in elementor editor mode
        add_action("elementor/editor/after_enqueue_scripts", [$this, 'pricing_editor_assets']);
        //hook for enqueue js in elementor frontend mode
        add_action("elementor/frontend/after_enqueue_scripts", [$this, 'progressbar_asets']);
	    
	//Register new widget category
        add_action( 'elementor/elements/categories_registered', [$this, 'add_elementor_widget_categories'] );
	
    }
    function progressbar_asets(){
        //Enqueue js in editor mode
        wp_enqueue_script("progressbar-js", plugins_url("/assets/js/progressbar.min.js",__FILE__), array('jquery'), time(), true);
    }
    function pricing_editor_assets(){
        //Enqueue js
        wp_enqueue_script("pricing-editor-js", plugins_url("/assets/js/main.js",__FILE__), array('jquery'), '1.0', true);
    }
    function widget_styles(){
        //Enqueue css
        wp_enqueue_style("froala-css", "//cdnjs.cloudflare.com/ajax/libs/froala-design-blocks/2.0.1/css/froala_blocks.min.css");
    }
    //Custom widget register	
    public function add_elementor_widget_categories( $elements_manager ) {

        $elements_manager->add_category(
            'custom',
            [
                'title' => __( 'Custom', 'timerelement' ),
                'icon' => 'fa fa-plug',
            ]
        );
    
    }
    public function admin_notice_missing_main_plugin() {

        if ( isset( $_GET['activate'] ) ) {
            unset( $_GET['activate'] );
        }

        $message = sprintf(
            /* translators: 1: Plugin name 2: Elementor */
            esc_html__( '"%1$s" requires "%2$s" to be installed and activated.', 'timerelement' ),
            '<strong>' . esc_html__( 'Elementor Test Extension', 'timerelement' ) . '</strong>',
            '<strong>' . esc_html__( 'Elementor', 'timerelement' ) . '</strong>'
        );

        printf( '<div class="notice notice-warning is-dismissible"><p>%1$s</p></div>', $message );

    }

    public function admin_notice_minimum_elementor_version() {

		if ( isset( $_GET['activate'] ) ) unset( $_GET['activate'] );

		$message = sprintf(
			/* translators: 1: Plugin name 2: Elementor 3: Required Elementor version */
			esc_html__( '"%1$s" requires "%2$s" version %3$s or greater.', 'timerelement' ),
			'<strong>' . esc_html__( 'Elementor Test Extension', 'timerelement' ) . '</strong>',
			'<strong>' . esc_html__( 'Elementor', 'timerelement' ) . '</strong>',
			 self::MINIMUM_ELEMENTOR_VERSION
		);

		printf( '<div class="notice notice-warning is-dismissible"><p>%1$s</p></div>', $message );

    }
    public function admin_notice_minimum_php_version() {

		if ( isset( $_GET['activate'] ) ) unset( $_GET['activate'] );

		$message = sprintf(
			/* translators: 1: Plugin name 2: PHP 3: Required PHP version */
			esc_html__( '"%1$s" requires "%2$s" version %3$s or greater.', 'timerelement' ),
			'<strong>' . esc_html__( 'Elementor Test Extension', 'timerelement' ) . '</strong>',
			'<strong>' . esc_html__( 'PHP', 'timerelement' ) . '</strong>',
			 self::MINIMUM_PHP_VERSION
		);

		printf( '<div class="notice notice-warning is-dismissible"><p>%1$s</p></div>', $message );

	}

    public function init_widgets() {
        //All widget file will go here
		require_once( __DIR__ . '/widgets/progressbar-widget.php' );

		//instance all widget classes
		\Elementor\Plugin::instance()->widgets_manager->register_widget_type( new \Elementor_Progressbar_Widget() );

    }


}
TimerElementExtension::instance();