How to use is_post_type_viewable filter in WordPress

Hey there! If you’re diving into WordPress development, understanding hooks is super important. One of these hooks is the is_post_type_viewable filter. Let’s take a closer look at how you can use this filter in your projects.

The returned filtered value must be a boolean type to ensure is_post_type_viewable() only returns a boolean. This strictness is by design to maintain backwards-compatibility and guard against potential type errors in PHP 8.1+. Non-boolean values (even falsey and truthy values) will result in the function returning false.

To use the is_post_type_viewable filter, first, you have to register it using add_filter. You can write this code into the functions.php of your activated theme or in a custom WordPress Plugin. At WePlugins, we always prefer to create a custom WordPress Plugin while using hooks so nothing breaks when you update your WordPress Theme in the future.

In the below live example, we have defined a function weplugins_modify_is_post_type_viewable_defaults which takes 2 parameters and we registered using add_filter. The first parameter is_post_type_viewable is the name of the hook, the second parameter weplugins_modify_is_post_type_viewable_defaults is the name of the function which needs to be called, the third parameter is the priority of calling the hook if the same hook is used multiple times, and the last parameter is the number of arguments (if any) to be passed in the registered function.

Sometimes, you have to remove a registered hook so you can use remove_filter to remove the is_post_type_viewable filter.

Parameters

Below are the 2 parameters required to use this hook:

• $is_viewable: (bool) Whether the post type is “viewable” (strict type).
• $post_type: (WP_Post_Type) Post type object.

Live Example 1: Basic Usage

Below is an example of how you can use this hook:

    function weplugins_modify_is_post_type_viewable_defaults($is_viewable, $post_type) { 
        // Update the $is_viewable variable according to your website requirements and return this variable. 
        // You can modify the $is_viewable variable conditionally too if you want.
        return $is_viewable; 
    }
    // add the filter
    add_filter("is_post_type_viewable", "weplugins_modify_is_post_type_viewable_defaults", 10, 2);
    

Live Example 2: Conditional Viewability

In this example, we conditionally modify the viewability based on the post type:

    function weplugins_modify_is_post_type_viewable_defaults($is_viewable, $post_type) {
        if ($post_type->name == 'my_custom_post_type') {
            $is_viewable = false;
        }
        return $is_viewable;
    }
    add_filter("is_post_type_viewable", "weplugins_modify_is_post_type_viewable_defaults", 10, 2);
    

Live Example 3: Removing a Hook Callback

To remove a hook callback, use the example below. Please make sure to provide the same callback function name, priority, and number of arguments while removing the hook callback:

    remove_filter("is_post_type_viewable", "weplugins_modify_is_post_type_viewable_defaults", 10, 2);
    

Contact Us

If you’re having any trouble using this hook or need customization, please contact us. We’d be happy to assist you!