Show control conditionally in Gutenberg

There are 2 main issues in your code:

1. What is that restrict in your OptionsPanel component? Where and how you defined it?

2. Both the onUpdateRestrict and onUpdateSubscribe are not functions, so clicking on the toggle controls will result in a JavaScript error.

And if you can show your complete code, I can probably help you fix your code. However, I suggest you to try the compose package to build the OptionsPanel component because doing it that way can greatly help reduce the source and make things quite easy for us.

So with the compose package, the steps are:

Note: I’m using these two meta keys: restrict_viewing and subscribe_to_news, so be sure to change them to the correct ones. (I.e. Use the proper meta keys.)

1. Load all WordPress dependencies:

   import { PluginDocumentSettingPanel } from '@wordpress/edit-post';
   import { ToggleControl } from '@wordpress/components';
   import { __ } from '@wordpress/i18n';
   import { registerPlugin } from '@wordpress/plugins';
   import { withSelect, withDispatch } from '@wordpress/data';
   import { compose } from '@wordpress/compose';
   

2. Create the primary component which basically simply renders the plugin/sidebar panel plus the two toggle controls (the RestrictControl & SubscribeControl in the question).

   function OptionsPanelComponent( {
       // These props are passed by applyWithSelect(). (see step #3)
       currentPostType, // current post type
       restrictViewing, // current state of the meta restrict_viewing
       subscribeToNews, // current state of the meta subscribe_to_news
       // And these are passed by applyWithDispatch(). (see step #4)
       onUpdateRestrict,  // function which updates the meta restrict_viewing
       onUpdateSubscribe, // function which updates the meta subscribe_to_news
   } ) {
       if ( 'custom_type' !== currentPostType ) {
           return null;
       }
   
       return (
           <PluginDocumentSettingPanel
               name="options"
               title={ __( 'Options' ) }
               className="options-panel"
           >
               <ToggleControl
                   label={ __( 'Restrict viewing?' ) }
                   checked={ restrictViewing }
                   onChange={ onUpdateRestrict }
               />
               { restrictViewing && (
                   <ToggleControl
                       label={ __( 'Add to newsletter?' ) }
                       checked={ subscribeToNews }
                       onChange={ onUpdateSubscribe }
                   />
               ) }
           </PluginDocumentSettingPanel>
       );
   }
   

3. Use wp.data.withSelect to ‘select’/retrieve data from the current post (that’s being edited) and pass the data to the above component (OptionsPanelComponent).

   Note: The select is always passed to the function and that select is equivalent to wp.data.select.

   const applyWithSelect = withSelect( ( select ) => {
       const {
           getEditedPostAttribute,
           getCurrentPostType
       } = select( 'core/editor' );
   
       const meta = getEditedPostAttribute( 'meta' );
   
       return {
           currentPostType: getCurrentPostType(),
           restrictViewing: meta.restrict_viewing,
           subscribeToNews: meta.subscribe_to_news,
       };
   } );
   

4. Use wp.data.withDispatch to define the functions for updating the post data and pass the functions to the component in step #2 above (OptionsPanelComponent).

   Note: The dispatch is always passed to the function and that dispatch is equivalent to wp.data.dispatch.

   const applyWithDispatch = withDispatch( ( dispatch ) => {
       const { editPost } = dispatch( 'core/editor' );
   
       return {
           onUpdateRestrict( restrict ) {
               const meta = { restrict_viewing: restrict };
               editPost( { meta } );
           },
           onUpdateSubscribe( subscribe ) {
               const meta = { subscribe_to_news: subscribe };
               editPost( { meta } );
           },
       };
   } );
   

5. Then finally, use wp.compose.compose() to ‘compose’/wrap all the three components above (they might be defined using function or const, but they really are components). And this ‘composed’ component will be the one we pass as the render callback for wp.plugins.registerPlugin.

   const OptionsPanel = compose(
       applyWithSelect,
       applyWithDispatch
   )( OptionsPanelComponent );
   
   registerPlugin( 'options-panel', {
       render: OptionsPanel,
   } );
   

Full Code I used for testing purposes

You can find it here, or you can download the full plugin which I created based on this example.

And I have tried & tested that on WordPress 5.4.1 with the default post post type with the two meta keys mentioned earlier in this answer.

Alternate Solution

If you don’t want to use compose(), then you can try this one. But I’m adding that just because I thought it would be useful to myself in the future. 🙂