Filter and options

“Use for Variations” – this option determines how to filter variable products – by the value of the attribute of the variations or by the value of the attribute of the parent product.

For example, this is a filter by Color and some variable (parent) product has a Blue color. But its variations have Blue, Green, and Red colors. If you disable the “Use for Variations” option for the color filter, then this product will be available only when you select the color “Blue” (i.e., as specified for the parent product). And if you enable this option, then this product will be available when you select any of the three colors – “Blue”, “Green”, or “Red” – because the filter will look for matches in the variations, not in the parent product.

So, using this option, you can define the filtering mode for variable products that suits you.

Parent filter – this option is useful in situations where filtering is performed step by step and the terms of one filter depend on the selection of terms of another. A popular and illustrative example is the situation with Car Brand and Car Model. The user usually selects the Brand first, for example, VolksWagen, and then a specific Model – Golf, Passat, or Tuareg. And when they have chosen VolksWagen, it makes no sense to show irrelevant models such as Land Cruiser, Camry, or Corolla in the Car Model filter, because they belong to a completely different Brand. Instead, it makes sense to display only those that match the selected Volkswagen Brand.

The Parent filter option was created for this and similar situations. In this example, for the Car Model filter, it is enough to specify the Car Brand filter as the Parent filter value, and then all models available in this filter will appear in it only after selecting a specific Brand. That is, it will be impossible to select a Model without first specifying a Brand.

Also, the “Hide until the Parent is selected” option allows you to completely hide this filter until some parent value is selected.

Sometimes you may need to create two or more Filters based on the same criterion within a single Filter Set. Let’s say right away that this is technically impossible, but there are ways to solve this problem.

This need arises as a result of poor organization of the data structure. For example, when the same taxonomy is used for different purposes. Let’s imagine that you have a regular Post Category and you have divided its terms into two groups, Size and Color. You created the parent category Size and created the sizes S, M, L, XL, XXL and assigned them as child categories to the Size category. And for the Color category, you created and assigned White, Green, Blue, Black as children. And then you need to create two Filters – by Size and by Color – in one Filter Set and use the Include/Exclude option to specify the necessary terms for each of the Filters. Although technically, these are essentially two Filters by the same entity – the Post Category. Unfortunately, this is not possible for technical reasons, because a Filter Set can contain only one Filter by the same entity.

Two ways to solve the problem

If things haven’t gotten that far and you have the ability to create separate custom Size and Color taxonomies, as in our example above, without a lot of time and effort, then you should create them. This can be done, for example, with the CPTUI plugin or with program code. Otherwise, you will often have to divide your categories into separate groups – Size and Color – in many places on the site. When these are separate taxonomies, you will be able to work with them independently of each other and then it will obviously be easy for you to create two separate Filters within one Filter Set.

If things have gone too far and you cannot abandon this organization of taxonomy terms, or if changes will require a lot of time and effort, you can use a life hack – create two Filter Sets for the same page and insert the necessary Filters into each of them and configure the appropriate terms for them.

This life hack will allow you to use two different Filters by the same criterion on the same page, but this configuration will not be compatible with the “Pop-up Filters widget” option.

It is up to you to decide which way to solve this problem is best for you.

If none of the existing sorting options works for you, you can sort the terms using program code.
Here is an example of how to sort terms by the menu_order value of a term object.

/* Let's sort Color filter terms by the menu_order */
add_filter('wpc_terms_before_display', 'wpc_sort_terms_as_needed', 10, 2);
function wpc_sort_terms_as_needed($terms, $filter){
    // pa_color - is desired taxonomy
    if ($filter['e_name'] === 'pa_color') {
        $newTerms = [];
        foreach ($terms as $k => $term) {
            $termOrder = get_term_meta($term->term_id, 'order', true);
            $term->menu_order = ($termOrder !== false) ? $termOrder : 0;
            $newTerms[$k] = $term;
        }

        // To sort in descending order
        // usort( $newTerms, \FilterEverything\Filter\EntityManager::compareDesc('menu_order') );
        // To sort in ascending order
        usort($newTerms, \FilterEverything\Filter\EntityManager::compareAsc('menu_order'));

        return $newTerms;
    }

    return $terms;
}

Parameters

• $terms (array) List of term objects
• $filter (array) Current Filter parameters
• $set (array) Filter Set fields with parameters
• $urlManager (object) Of the UrlManager Class, that can be used to get the link to the filter