How to use get_option() in Gutenberg block editor to retrieve global settings?

If your option is enabled in the REST API, e.g. by using register_setting() with 'show_in_rest' => true, you can use wp.data.select( 'core' ).getSite() to retrieve the value of your option, and to update the option, you can use wp.data.dispatch( 'core' ).saveSite().

So for example in your case:

• To get the option value: wp.data.select( 'core' ).getSite()?.autoupdate

• To update the option (to true): wp.data.dispatch( 'core' ).saveSite( { autoupdate: true } )

  Note: This function will make an AJAX request to the Site Settings endpoint, so you will need to wait a while before getSite() returns the updated options.

Example using useSelect and useDispatch in the edit function:

// In the `edit` function:

// Get the current option value.
const autoupdate = useSelect(
    ( select ) => select( 'core' ).getSite()?.autoupdate,
    []
);

// Extract the function which saves the new option value.
const { saveSite } = useDispatch( 'core' );

// Save the new option value.
function saveAutoupdate( autoupdate ) {
    saveSite( { autoupdate } );
}

return (
    <div { ...useBlockProps() }>
        <CheckboxControl
            label="Auto-Update"
            help="Additional help text"
            checked={ !! autoupdate }
            onChange={ saveAutoupdate }
        />
    </div>
);