Conditional display

Containers are very flexible in terms of display options. By default, containers show on all related entities (all post types for post meta container, all terms for term meta container etc.), however, you can limit container visibility to specific post types, taxonomy terms, hierarchy levels and more with unlimited complexity.

Adding a display condition to a container is done by using one of the following methods:

• ->where( $condition, $comparison_operator, $value ) – adds a condition with an AND relation to other conditions
• ->or_where( $condition, $comparison_operator, $value ) – adds a condition with an OR relation to other conditions

Note: chaining conditions behaves exactly like a normal php if statement with multiple conditions.

Parameter	Description
$condition	A condition type name as a string (refer to the Container Types page)
$comparison_operator	Can be one of the following: '=', '!=', '>', '>=', '<', '<=', 'IN', 'NOT IN', 'CUSTOM'
$value	The value to check against. IN and NOT IN operators expect an array; CUSTOM operator expects a callable

Note: You can use an anonymous function as the $value parameter for all comparison operators in order to lazyload the value which can be very useful when evaluating the value is a resource-intensive task.

The CUSTOM comparison operator

This operator allows you to supply a callable which must return a boolean value whether this condition is fulfilled or not. This way you have more control over how a value is compared if the built-in functionality does not suit your needs.

For example, if you wish to have a container only display on pages on even levels in the hierarchy your code will look like this:

Container::make( 'post_meta', 'Custom Data' )
    ->where( 'post_type', '=', 'page' )
    ->where( 'post_level', 'CUSTOM', function( $post_level ) {
        return ( $post_level % 2 === 0 );
    } );

Examples

Showing a Post Meta Container on all pages

Container::make( 'post_meta', 'Custom Data' )
    ->where( 'post_type', '=', 'page' )
    ->add_fields( array( ... ) );

Showing a User Meta Container only if the current user is an administrator or editor

Container::make( 'post_meta', 'Custom Data' )
    ->where( 'current_user_role', 'IN', array( 'administrator', 'editor' ) )
    ->add_fields( array( ... ) );

Nested logic

In order to achieve nested display logic the when() and or_when() methods also support being invoked with a callable:

Container::make( 'post_meta', 'Custom Data' )
    ->where( function( $lvl1_condition ) {
        $lvl1_condition->where( $condition, $comparison_operator, $value );
        $lvl1_condition->where( function( $lvl2_condition ) {
            ... // can be nested infinitely
        } );
        ...
    } );

For example, to have a container visible on all post types if the current user is an administrator OR only on the page post type if the current user is an editor your code will look like this:

Container::make( 'post_meta', 'Custom Data' )
    ->where( 'current_user_role', '=', 'administrator' )
    ->or_where( function( $condition ) {
        $condition->where( 'current_user_role', '=', 'editor' );
        $condition->where( 'post_type', '=', 'page' );
    } );