Check if current category has subcategories

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' ) {

Answers:

Thank you for visiting the Q&A section on Magenaut. Please note that all the answers may not help you solve the issue immediately. So please treat them as advisements. If you found the post helpful (or not), leave a comment & I’ll get back to you as soon as possible.

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