Bye-bye Meta Boxes, Hello Gutenberg Sidebars

By the way, the tutorial about WordPress Meta Boxes is my first tutorial on this blog, but now time of Meta Boxes is over…

Below is the correct tutorial about creating Gutenberg sidebar panel settings. I say correct, because when I learned this I found some tutorials which suggest you to work directly with WordPress REST API and use wp.apiRequest etc. Please skip such tutorials, because those implementations will cause bugs.

Let’s begin! ?

I personally don’t work with Yoast plugin, not because I do not like it, I just think that it is too heavy, so I store my posts SEO settings in post meta. And here is what we will create in this tutorial:

The cool thing here is that you can create as much these sidebar “tabs” as you want and each of them can contain a lot of fields. You can deactivate a certain sidebar tab if you click on the star icon.

One more thing – if you do not want deal with all of the code below, I recommend you an alternate way to create Gutenberg sidebars – just with small PHP code snippets for the functions.php file.

Step 1. Register Meta Keys in REST API

I am going to use these 3 meta keys – misha_plugin_seo_title, misha_plugin_seo_description and misha_plugin_seo_robots.

Nothing super especial right now, you just have to register all of the keys in REST API. Code for your functions.php / custom plugin:

// you have to use it within the "init" hook
add_action( 'init', function(){
 
	register_meta( 'post', 'misha_plugin_seo_title', array(
 		'type'		=> 'string',
 		'single'	=> true,
 		'show_in_rest'	=> true,
 	) );
 
	register_meta( 'post', 'misha_plugin_seo_description', array(
 		'type'		=> 'string',
 		'single'	=> true,
 		'show_in_rest'	=> true,
 	) );
 
	register_meta( 'post', 'misha_plugin_seo_robots', array(
 		'type'		=> 'boolean', // because it is a checkbox
 		'single'	=> true,
 		'show_in_rest'	=> true,
 	) );
 
});

Of course, you can check the documentation of the register_meta() function, but I will describe the parameters we used here shortly.

• post – object type we register meta for. Object types are post, term, comment or user, so for Gutenberg sidebars we are going to use post only.
• type – the type of data, can be string, boolean, integer or number,
• single equal to true means, that our meta has only one value.

Why I used boolean type for robots meta key? Because I do not use anything except noindex/follow, so, the checkbox above will add only this value once checked.

Step 2. Enqueue Scripts

I want to highlight this step too, because I think you have to pay attention to dependencies:

add_action( 'enqueue_block_editor_assets', function(){
 
	wp_enqueue_script(
		'misha-sidebar',
		get_stylesheet_directory_uri() . '/sidebar.js',
		array( 'wp-i18n', 'wp-blocks', 'wp-edit-post', 'wp-element', 'wp-editor', 'wp-components', 'wp-data', 'wp-plugins', 'wp-edit-post' ),
		filemtime( dirname( __FILE__ ) . '/sidebar.js' )
	);
 
});

At you can see, comparing to registering a regular Gutenberg block, here are a lot of dependencies. The above code can be placed in your theme / child theme functions.php or in a custom plugin, but please be careful with the path on line 7.

And I already know that I have to mention that too – at this moment sidebar.js is just an empty file ?

In case you want to allow / disable your sidebar depending on a custom post type, you can use get_current_screen()-based condition at the beginning of the action hook:

add_action( 'enqueue_block_editor_assets', function(){
 
	$screen = get_current_screen();
	if( $screen->post_type === 'page' ) return; // disabled for Pages
 
	wp_enqueue_script(
 
		...

Step 3. Components

In this step let’s decide which React components we will need.

( function( plugins, editPost, element, components, data, compose ) {
 
	const el = element.createElement;
 
	const { Fragment } = element;
	const { registerPlugin } = plugins;
	const { PluginSidebar, PluginSidebarMoreMenuItem } = editPost;
	const { PanelBody, TextControl, TextareaControl, CheckboxControl } = components;
	const { withSelect, withDispatch } = data;
 
 
	const MetaTextControl = ...
	const MetaTextareaControl = ...
	const MetaCheckboxControl = ...
 
	registerPlugin( 
		...
	);
 
} )(
	window.wp.plugins,
	window.wp.editPost,
	window.wp.element,
	window.wp.components,
	window.wp.data,
	window.wp.compose
);

Here is just a skeleton, how your sidebar.js file will look like. You can copy the above code to the file right away.

Probably you see here some familiar components, like PanelBody, TextControl etc on line 7, which were explained in details in my previous tutorial. All the new components I will describe below.

Step 4. registerPlugin

Ok, here is a lot of code but everything is explained after it.

registerPlugin( 'misha-seo', {
	render: function() {
		return el( Fragment, {},
			el( PluginSidebarMoreMenuItem,
				{
					target: 'misha-seo',
					icon: mishaIcon,
				},
				'SEO'
			),
			el( PluginSidebar,
				{
					name: 'misha-seo',
					icon: mishaIcon,
					title: 'SEO',
				},
				el( PanelBody, {},
					// Field 1
					el( MetaTextControl,
						{
							metaKey: 'misha_plugin_seo_title',
							title : 'Title',
						}
					),
					// Field 2
					el( MetaTextareaControl,
						{
							metaKey: 'misha_plugin_seo_description',
							title : 'Description',
						}
					),
					// Field 3
					el( MetaCheckboxControl,
						{
							metaKey: 'misha_plugin_seo_robots',
							title : 'Hide from search engines',
						}
					),
				)
			)
		);
	}
} );

• mishaIcon is a variable you have to set before which either points to an icon from Dashicons set (example: admin-post) or contains a SVG icon. Read this tutorial to learn more.
• Do not forget about PluginSidebarMoreMenuItem – it just adds your sidebar panel to “Plugins” section here:

• MetaTextControl, MetaTextareaControl and MetaCheckboxControl are just my custom components which extend as you could guess TextControl, TextareaControl and CheckBox control. We have to do it, because it is not enough just to display certain fields in sidebar panels, we have to get their values from post meta and update the values as well.

Step 5. withDispatch, withSelect

The long story short – using regular Gutenberg control components like TextControl or ToggleControl etc is not enough, because they don’t allow us go get or set values in post meta.

That’s why we compose them into a HOC (Higher Order Component):

• After wrapping TextControl in withSelect() we have the possibility to access metaValue property on line 30,
• After wrapping it in withDispatch() we receive the possibility to use setMetaValue() on line 32 which allows to update the meta values correctly.

var MetaTextControl = compose.compose(
	withDispatch( function( dispatch, props ) {
		return {
			setMetaValue: function( metaValue ) {
				dispatch( 'core/editor' ).editPost(
					{ meta: { [ props.metaKey ]: metaValue } }
				);
			}
		}
	} ),
	withSelect( function( select, props ) {
		return {
			metaValue: select( 'core/editor' ).getEditedPostAttribute( 'meta' )[ props.metaKey ],
		}
	} ) )( function( props ) {
		return el( TextControl, {
			label: props.title,
			value: props.metaValue,
			onChange: function( content ) {
				props.setMetaValue( content );
			},
		});
	}
);

According to the step 4 I created higher order components for each inspector control – MetaTextControl, MetaTextareaControl and MetaCheckboxControl, but the components code is very similar, so for some situations it would be better to create just one component, let’s say MetaControl and pass control type in it.

And a small bonus for you – just in case your would like to hide certain controls in your sidebar depending on a custom post type:

withSelect( function( select, props ) {
	return {
		metaValue: select( 'core/editor' ).getEditedPostAttribute( 'meta' )[ props.metaKey ],
		postType: select("core/editor").getCurrentPostType(),
	}
} ) )( function( props ) {
	if ( props.postType == 'page' ) {
		return null;
	}
	return el( TextControl, {
 
	...

See also

• How to Create Gutenberg Sidebars using only PHP
• More about Inspector Controls
• Color Palette for a Custom Block (my first tutorial with HOC)