Check if current category has subcategories

The question:

I have found the following piece of code in the WP Knowledge Base theme in order to show subcategories of a parent category. The problem is that this only works for the first level of hierarchy, so I wanted to change the if clause in order to check if the current category has children but I have no clue how to do that, any idea?
Thanks

global $term_meta, $cat, $cat_id, $wp_query;

// Check if the current category is not a first level category
// This will happen if the current category does not have any child
// If this is the case, then we simply show all it's posts
// Instead of the nice knowledgebase type things
if ( $cat->parent != '0' ) {

The Solutions:

Below are the methods you can try. The first solution is probably the best. Try others if the first one doesn’t work. Senior developers aren’t just copying/pasting – they read the methods carefully & apply them wisely to each case.

Method 1

You could use this simple function call which returns either TRUE or FALSE depending on if $children is an empty array or not.

/**
 * Check if given term has child terms
 *
 * @param Integer $term_id
 * @param String $taxonomy
 *
 * @return Boolean
 */
function category_has_children( $term_id = 0, $taxonomy = 'category' ) {
    $children = get_categories( array( 
        'child_of'      => $term_id,
        'taxonomy'      => $taxonomy,
        'hide_empty'    => false,
        'fields'        => 'ids',
    ) );
    return ( $children );
}

So if you’re only using the built-in post categories you can call the function like so: category_has_children( 17 );

If you need to test a custom taxonomy it will work almost the same, you’ll just need to pass in an extra parameter ‘taxonomy-slug’: category_has_children( 7, 'my_taxonomy' );

To call it in your IF statement:

if( $cat->parent != 0 && ! category_has_children( $cat->term_id ) )

Method 2

There is a build in function for this already, no need to create a custom function for this. The function is called get_term_children() and will return either

  • An array of child terms if the given term have children

  • An empty array if no child terms are found

  • WP_Error object if the taxonomy does not exist

With this in mind, wrap get_term_children() in a function and return true or false depending on the returned value if you just need a boolean value ( like a conditional tag )

function has_term_have_children( $term_id = '', $taxonomy = 'category' )
{
    // Check if we have a term value, if not, return false
    if ( !$term_id ) 
        return false;

    // Get term children
    $term_children = get_term_children( filter_var( $term_id, FILTER_VALIDATE_INT ), filter_var( $taxonomy, FILTER_SANITIZE_STRING ) );

    // Return false if we have an empty array or WP_Error object
    if ( empty( $term_children ) || is_wp_error( $term_children ) )
    return false;

    return true;
}

You can simply now just pass the term id to the function and the correct taxonomy name if the taxonomy is anything other than category, and you will get a boolen value back just as the build in conditional tags, true on success if the term have children, false if it does not.

if ( has_term_have_children( 21 ) ) {
    // Do something if term 21 have children
}

Method 3

To get the name of the child categories. I have used @Howdy_McGee’s function for a quicker & iterative process.

function category_has_children( $term_id = 0, $post_type = 'post', $taxonomy = 'category' ) {

    $children = get_categories( array( 'child_of' => $term_id, 'type' => $post_type, 'taxonomy' => $taxonomy, 'order' => 'ASC', 'orderby' => 'name' ) );
    if($children){
    echo '<ul>';
    foreach ($children as $value) {
        echo '<li>';
            echo '<a href="'.get_bloginfo(" rel="nofollow noreferrer noopener"siteurl").'/category/'.$value->slug.'" >'.$value->name.'</a>';
        echo '</li>';
        }
    echo '</ul>';
    }
}

$cId = get_cat_id('cms'); /* cms is the parent category */
category_has_children($cId, 'post', 'category');

This will list all the sub-category (child) of a parent category.

Method 4

This is what I use. The variable $cat is the category ID you are checking:

$categories = get_categories($cat);

if (!empty($categories)) {
    // This Category has children
    }
else {
    // This category has no children
    }

Method 5

Use this function cat_has_subcat('paste cat id') to check the category has any subcategories or not

//paste it in your function.php

//start


function cat_has_subcat($catId){
    $args = array(
        'taxonomy' => 'product_cat',
        'orderby' => 'name',
        'parent' => $catId,
        'show_count' => 0,
        'pad_counts' => 0,
        'hierarchical' => 1,
        'title_li' => '',
        'hide_empty' => false
    );

    $cats = get_categories($args);
    if(!empty($cats)){
        return $catId;
    }
}

//end


All methods was sourced from stackoverflow.com or stackexchange.com, is licensed under cc by-sa 2.5, cc by-sa 3.0 and cc by-sa 4.0

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