I recently wrote a WordPress plugin called Organize Drafts, which creates a custom taxonomy called Draft Types (using the slug lswdrafttype). This taxonomy is used to organize drafts of pages and posts, as well as (optionally) custom post types.

My plugin uses a custom meta box that displays a dropdown of draft types to choose from. I only want this meta box to appear on drafts, not on published, scheduled, or any other type of post/page.

Here’s how it looks now – for a Draft Post

Here’s how it looks now – for a Published Post

Current Code

Currently, my plugin checks the post_status in the function that renders the meta box, and then display a message instead of the drop down, like this:

public static function update_meta_boxes() {
    $post_types = apply_filters('lsw_default_post_types', LSW_Organize_Drafts::$post_types);
    remove_meta_box( 'tagsdiv-lswdrafttype', $post_types, 'side' );
    add_meta_box('lswdrafttype_custom', __('Draft Type', 'lsw_organize_drafts'), array('LSW_Organize_Drafts',
            'render_meta_box'), $post_types, 'side', 'core');
}

public static function render_meta_box($post) {
    if($post->post_status!=='draft') {
        printf( esc_html__( 'Not a draft' ));
        return;
    } else {
        //create dropdown form
    }
}

This is less than ideal, for 2 reasons:

• The box still displays on published posts, and that’s ugly.
• When a new post is created, initially it has no post_status (I think prior to the first autosave) so the dropdown menu doesn’t appear.

What I’m Thinking of Changing

I know that I can remove the meta box with Javascript but I don’t know if that’s the best option, and I also don’t know if I should use Ajax to accomplish this task?

I’m thinking that when the edit post page is loaded, the ajax request would send the post_ID and then the ajax callback function would check for the post_status. If the post_status was empty or a draft, the box would be displayed, but otherwise, I’d remove it.

Are there any pitfalls in doing it this way? Is there a better solution?

I will suggest to check the $post object in PHP before adding meta box.
And add the meta box if status is draft or auto-draft.

Consider this code

function update_meta_boxes($current_post_type, $post) {
    $post_types = apply_filters('lsw_default_post_types', LSW_Organize_Drafts::$post_types);
    remove_meta_box( 'tagsdiv-lswdrafttype', $post_types, 'side' );
    if (isset($post->post_status) && ($post->post_status == 'draft' || $post->post_status == 'auto-draft')) {
        add_meta_box('lswdrafttype_custom', __('Draft Type', 'lsw_organize_drafts'), array('LSW_Organize_Drafts','render_meta_box'), $post_types, 'side', 'core');
    }

}
add_action( 'add_meta_boxes', 'update_meta_boxes', 10, 2);