Is Gutenberg active

is-gutenberg-active.php

<?php

function prefix_is_gutenberg_active() {
	include_once ABSPATH . 'wp-admin/includes/plugin.php';

	$is_gutenberg      = has_filter( 'replace_editor', 'gutenberg_init' ) || version_compare( $GLOBALS['wp_version'], '5.0-beta', '>' );
	$is_classic_editor = is_plugin_active( 'classic-editor/classic-editor.php' ) && get_option( 'classic-editor-replace' ) === 'no-replace';

	if ( $is_gutenberg && ! $is_classic_editor ) {
		return true;
	}

	return false;
}