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