get_term_children() WP 1.0

Merge all term children into a single array of their IDs.

This recursive function will merge all of the children of $term into the same array of term IDs. Only useful for taxonomies which are hierarchical.

Will return an empty array if $term does not exist in $taxonomy.

No Hooks.

Return

Array/WP_Error. List of Term IDs. WP_Error returned if $taxonomy does not exist.

Usage

get_term_children( $term_id, $taxonomy );

$term_id(int) (required)

ID of Term to get children.

$taxonomy(string) (required)

Taxonomy Name.

Changelog

Code of get term children: wp-includes/taxonomy.php ^{WP 5.4.2}

<?php
function get_term_children( $term_id, $taxonomy ) {
	if ( ! taxonomy_exists( $taxonomy ) ) {
		return new WP_Error( 'invalid_taxonomy', __( 'Invalid taxonomy.' ) );
	}

	$term_id = intval( $term_id );

	$terms = _get_term_hierarchy( $taxonomy );

	if ( ! isset( $terms[ $term_id ] ) ) {
		return array();
	}

	$children = $terms[ $term_id ];

	foreach ( (array) $terms[ $term_id ] as $child ) {
		if ( $term_id === $child ) {
			continue;
		}

		if ( isset( $terms[ $child ] ) ) {
			$children = array_merge( $children, get_term_children( $child, $taxonomy ) );
		}
	}

	return $children;
}

Related Functions

From tag: Relations (of posts terms...)

More from tag: Term (taxonomies terms)

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