Add Genesis layout class to Gutenberg editor pages (admin)

add-editor-layout-classes.js

// Add genesis layout classes to the Block Editor.
// File lives in the theme's /js/ folder.
wp.domReady(function () {
    yourTheme.updateLayoutClass();

    var layouts = document.querySelector(".genesis-layout-selector");
    layouts.addEventListener("input", function (e) {
        yourTheme.updateLayoutClass();
    });
});

var yourTheme = {
    getLayout: function () {
        var inputs = document.querySelectorAll(".genesis-layout-selector input");
        var layout = "";
        for (var i = 0, len = inputs.length; i < len; i++) {
            if (inputs[i].checked) {
                layout = inputs[i].getAttribute("id");
                break;
            }
        }
        if (layout === "default-layout") layout = yourThemeConfig.defaultLayout;
        return layout;
    },

    setWrapperClass: function (layout) {
        var root = document.querySelector(".editor-writing-flow");
        var classes = root.classList;
        classes.forEach(function(c){
            if (c.includes("genesis-")) root.classList.remove(c);
        });
        root.classList.add("genesis-" + layout);
    },

    updateLayoutClass: function() {
        var layout = yourTheme.getLayout();
        yourTheme.setWrapperClass(layout);
    }
};

functions.php

<?php

add_action( 'enqueue_block_editor_assets', 'theme_name_block_editor_js' );
/**
 * Enqueue Gutenberg editor JavaScript to add layout body classes in the admin area.
 */
function theme_name_block_editor_js() {
	wp_enqueue_script(
		'your-theme-gutenberg-js',
		get_stylesheet_directory_uri() . '/js/add-editor-layout-classes.js',
		array( 'wp-dom' ),
		CHILD_THEME_VERSION,
		true
	);

	wp_localize_script( 'your-theme-gutenberg-js', 'yourThemeConfig', array(
		'defaultLayout' => genesis_get_default_layout(),
	));
}

// Add support for editor styles.
add_theme_support( 'editor-styles' );

// Enqueue editor styles.
add_editor_style( '/lib/gutenberg/style-editor.css' );

style-editor.css

/* Example of adjusting the wide block width in editor styles based on the 
   new genesis-content-sidebar classes the above script adds. */

.wp-block[data-align="wide"] {
	max-width: 1092px;
}

.genesis-content-sidebar .wp-block[data-align="wide"],
.genesis-sidebar-content .wp-block[data-align="wide"] {
	max-width: 800px;
}

/* Rest of styles here… */
/* See Genesis Sample for examples: https://github.com/studiopress/genesis-sample/blob/develop/lib/gutenberg/style-editor.css */