Integrating Gutenberg Blocks in Existing WordPress Plugins | https://www.ibenic.com/integrating-gutenberg-blocks-in-plugins

.babelrc

{
  "presets": [
    [
      "env",
      {
        "modules": false
      }
    ]
  ],
  "plugins": [
    "transform-object-rest-spread",
    [
      "transform-react-jsx",
      {
        "pragma": "wp.element.createElement"
      }
    ]
  ],
  "env": {
    "default": {
      "plugins": ["transform-runtime"]
    }
  }
}

.gitignore

node_modules/
.DS_Store

blocks.php

<?php

/**
 * Class MyPlugin_Blocks
 */
class MyPlugin_Blocks {

	/**
	 * MyPlugin_Blocks constructor.
	 */
	public function __construct() {
		add_action( 'plugins_loaded', array( $this, 'run' ) );
	}

	/**
	 * Run it and load Gutenberg blocks.
	 */
	public function run() {
		if ( ! function_exists( 'is_gutenberg_page' ) ) {
			return;
		}

		add_action( 'init', array( $this, 'register_blocks' ) );
	}
  
	/**
	 * Register the Blocks.
   * Const PLUGIN_FILE is a reference to the main plugin file, can be defined in the main file:
   * define( 'PLUGIN_FILE', __FILE__ );
	 */
	public function register_blocks() {
  
		wp_register_script(
			'myplugin-gutenberg',
			plugins_url( 'assets/dist/js/gutenberg.js', PLUGIN_FILE ),
			array( 'wp-blocks', 'wp-element' )
		);

		register_block_type( 'myplugin/myblock', array(
			'editor_script'   => 'myplugin-gutenberg'
		) );
	}
}

new MyPlugin_Blocks();

package.json

{
  "name": "my-plugin",
  "title": "My Plugin",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "start": "npm install && npm run watch",
    "dev": "cross-env webpack",
    "production": "cross-env NODE_ENV=production webpack",
    "build": "npm run production",
    "watch": "cross-env webpack --watch",
    "lint": "npm run lint:js & npm run lint:scss",
    "lint:js": "eslint assets/src/**/*.js blocks/**/*.js",
    "lint:scss": "stylelint assets/src/**/*.scss"
  },
  "dependencies": {
    "npm": "^5.7.1",
    "query-string": "^5.1.1",
    "script-loader": "^0.7.2"
  },
  "devDependencies": {
    "autoprefixer": "^7.2.6",
    "babel-core": "^6.26.3",
    "babel-eslint": "^8.2.6",
    "babel-loader": "^7.1.5",
    "babel-plugin-transform-object-rest-spread": "^6.26.0",
    "babel-plugin-transform-react-jsx": "^6.24.1",
    "babel-plugin-transform-runtime": "^6.23.0",
    "babel-polyfill": "^6.26.0",
    "babel-preset-env": "^1.7.0",
    "browser-sync": "^2.24.6",
    "browser-sync-webpack-plugin": "^1.2.0",
    "clean-webpack-plugin": "^0.1.19",
    "copy-webpack-plugin": "^4.5.2",
    "cross-env": "3.2.4",
    "css-loader": "^0.28.11",
    "cssnano": "^3.10.0",
    "eslint": "^4.19.1",
    "eslint-config-wordpress": "^2.0.0",
    "eslint-plugin-react": "^7.10.0",
    "expose-loader": "latest",
    "extract-text-webpack-plugin": "^3.0.0",
    "file-loader": "^1.1.11",
    "imagemin-webpack-plugin": "^1.6.1",
    "node-sass": "^4.9.1",
    "postcss-loader": "^2.1.6",
    "sass-loader": "^6.0.7",
    "style-loader": "^0.18.2",
    "stylelint-config-wordpress": "^12.0.0",
    "url-loader": "^0.5.9",
    "webpack": "^3.12.0",
    "webpack-rtl-plugin": "^1.7.0",
    "wp-pot": "latest"
  }
}

webpack-1.js

const webpack = require( 'webpack' ); // WebPack module
const CopyWebpackPlugin = require( 'copy-webpack-plugin' ); // command to copy files
const path = require( 'path' ); // for path
const ExtractTextPlugin = require( 'extract-text-webpack-plugin' ); // for extracting css/scss from JS
const inProduction = ('production' === process.env.NODE_ENV); // if in production
const ImageminPlugin = require( 'imagemin-webpack-plugin' ).default; // Optimize images
const CleanWebpackPlugin = require( 'clean-webpack-plugin' ); // To clean (remove files)
const WebpackRTLPlugin = require( 'webpack-rtl-plugin' ); // for RTL support (optional)
const wpPot = require( 'wp-pot' ); // For creating .pot files

const config = {
    // Ensure modules like magnific know jQuery is external (loaded via WP).
    externals: {
        $: 'jQuery',
        jquery: 'jQuery'
    },
    devtool: 'source-map',
    module: {
        rules: [

            // Use Babel to compile JS.
            {
                test: /\.js$/,
                exclude: /node_modules/,
                loaders: [
                    'babel-loader'
                ]
            },
        ]
    },
  
    plugins: [
        // Removes the "dist" folder before building.
        new CleanWebpackPlugin( [ 'assets/dist' ] ),
        
        // Extract CSS to /css/
        new ExtractTextPlugin( 'css/[name].css' ),

        // Create RTL css.
        new WebpackRTLPlugin()
    ]
};

webpack-2.js

// ... requires

const config = {
    // ...
    module: {
        rules: [

            // Use Babel to compile JS.
            {
                test: /\.js$/,
                exclude: /node_modules/,
                loaders: [
                    'babel-loader'
                ]
            },

            // Create RTL styles.
            {
                test: /\.css$/,
                loader: ExtractTextPlugin.extract( 'style-loader' )
            },

            // SASS to CSS.
            {
                test: /\.scss$/,
                use: ExtractTextPlugin.extract( {
                    use: [ {
                        loader: 'css-loader',
                        options: {
                            sourceMap: true
                        }
                    }, {
                        loader: 'postcss-loader',
                        options: {
                            sourceMap: true
                        }
                    }, {
                        loader: 'sass-loader',
                        options: {
                            sourceMap: true,
                            outputStyle: (inProduction ? 'compressed' : 'nested')
                        }
                    } ]
                } )
            },

            // Image files.
            {
                test: /\.(png|jpe?g|gif|svg)$/,
                use: [
                    {
                        loader: 'file-loader',
                        options: {
                            name: 'images/[name].[ext]',
                            publicPath: '../'
                        }
                    }
                ]
            }
        ]
    },

    // Plugins. Gotta have em'.
    plugins: [//...]
};

webpack-3.js

// ... requires
// ... config

module.exports = [
    // Adding entry points and output to the config.
    Object.assign({
        entry: {
            'frontend': ['./assets/frontend/style.scss', './assets/frontend/script.js'],
            'backend': ['./assets/backend/style.scss', './assets/backend/script.js'],
        },
        output: {
            path: path.join( __dirname, './assets/dist/' ),
            filename: 'js/[name].js',
        },
    }, config),
    // Adding our blocks JS as gutenberg.js and babel polyfill.
    Object.assign({
        entry: {
            'babel-polyfill': 'babel-polyfill',
            'gutenberg': './blocks/load.js'
        },

        // Tell webpack where to output.
        output: {
            path: path.resolve( __dirname, './resources/dist/' ),
            filename: 'js/[name].js'
        },
    }, config)
];

webpack-4.js

// ... requires
// ... config
// ... entry points

// inProd?
if ( inProduction ) {

    // POT file.
    wpPot( {
        package: 'my-plugin',
        domain: 'my-plugin',
        destFile: 'languages/my-plugin.pot',
        relativeTo: './',
    } );

    // Uglify JS.
    config.plugins.push( new webpack.optimize.UglifyJsPlugin( { sourceMap: true } ) );

    // Minify CSS.
    config.plugins.push( new webpack.LoaderOptionsPlugin( { minimize: true } ) );
}

webpack.config.js

const webpack = require( 'webpack' );
const CopyWebpackPlugin = require( 'copy-webpack-plugin' );
const path = require( 'path' );
const ExtractTextPlugin = require( 'extract-text-webpack-plugin' );
const inProduction = ('production' === process.env.NODE_ENV);
const BrowserSyncPlugin = require( 'browser-sync-webpack-plugin' );
const ImageminPlugin = require( 'imagemin-webpack-plugin' ).default;
const CleanWebpackPlugin = require( 'clean-webpack-plugin' );
const WebpackRTLPlugin = require( 'webpack-rtl-plugin' );
const wpPot = require( 'wp-pot' );

const config = {
    // Ensure modules like magnific know jQuery is external (loaded via WP).
    externals: {
        $: 'jQuery',
        jquery: 'jQuery'
    },
    devtool: 'source-map',
    module: {
        rules: [

            // Use Babel to compile JS.
            {
                test: /\.js$/,
                exclude: /node_modules/,
                loaders: [
                    'babel-loader'
                ]
            },

            // Create RTL styles.
            {
                test: /\.css$/,
                loader: ExtractTextPlugin.extract( 'style-loader' )
            },

            // SASS to CSS.
            {
                test: /\.scss$/,
                use: ExtractTextPlugin.extract( {
                    use: [ {
                        loader: 'css-loader',
                        options: {
                            sourceMap: true
                        }
                    }, {
                        loader: 'postcss-loader',
                        options: {
                            sourceMap: true
                        }
                    }, {
                        loader: 'sass-loader',
                        options: {
                            sourceMap: true,
                            outputStyle: (inProduction ? 'compressed' : 'nested')
                        }
                    } ]
                } )
            },

            // Image files.
            {
                test: /\.(png|jpe?g|gif|svg)$/,
                use: [
                    {
                        loader: 'file-loader',
                        options: {
                            name: 'images/[name].[ext]',
                            publicPath: '../'
                        }
                    }
                ]
            }
        ]
    },

    // Plugins. Gotta have em'.
    plugins: [

        // Removes the "dist" folder before building.
        new CleanWebpackPlugin( [ 'resources/dist' ] ),

        new ExtractTextPlugin( 'css/[name].css' ),

        // Create RTL css.
        new WebpackRTLPlugin()
    ]
};

module.exports = [
    Object.assign({
        entry: {
            'frontend': ['./resources/frontend/wp-convertkit.scss', './resources/frontend/wp-convertkit.js'],
            'backend': ['./resources/backend/wp-convertkit.scss', './resources/backend/wp-convertkit.js'],
        },
        output: {
            path: path.join( __dirname, './resources/dist/' ),
            filename: 'js/[name].js',
        },
    }, config),
    Object.assign({
        entry: {
            'babel-polyfill': 'babel-polyfill',
            'gutenberg': './blocks/load.js'
        },

        // Tell webpack where to output.
        output: {
            path: path.resolve( __dirname, './resources/dist/' ),
            filename: 'js/[name].js'
        },
    }, config)
];

// inProd?
if ( inProduction ) {

    // POT file.
    wpPot( {
        package: 'ConvertKit',
        domain: 'convertkit',
        destFile: 'languages/convertkit.pot',
        relativeTo: './',
    } );

    // Uglify JS.
    config.plugins.push( new webpack.optimize.UglifyJsPlugin( { sourceMap: true } ) );

    // Minify CSS.
    config.plugins.push( new webpack.LoaderOptionsPlugin( { minimize: true } ) );
}