Gets the subset of $terms that are descendants of $term_id.
Description
If $terms
is an array of objects, then _get_term_children() returns an array of objects.
If $terms
is an array of IDs, then _get_term_children() returns an array of IDs.
Parameters
$term_id
intrequired- The ancestor term: all returned terms should be descendants of
$term_id
. $terms
arrayrequired- The set of terms – either an array of term objects or term IDs – from which those that are descendants of $term_id will be chosen.
$taxonomy
stringrequired- The taxonomy which determines the hierarchy of the terms.
$ancestors
arrayoptional- Term ancestors that have already been identified. Passed by reference, to keep track of found terms when recursing the hierarchy. The array of located ancestors is used to prevent infinite recursion loops. For performance,
term_ids
are used as array keys, with 1 as value.Default:
array()
Source
function _get_term_children( $term_id, $terms, $taxonomy, &$ancestors = array() ) {
$empty_array = array();
if ( empty( $terms ) ) {
return $empty_array;
}
$term_id = (int) $term_id;
$term_list = array();
$has_children = _get_term_hierarchy( $taxonomy );
if ( $term_id && ! isset( $has_children[ $term_id ] ) ) {
return $empty_array;
}
// Include the term itself in the ancestors array, so we can properly detect when a loop has occurred.
if ( empty( $ancestors ) ) {
$ancestors[ $term_id ] = 1;
}
foreach ( (array) $terms as $term ) {
$use_id = false;
if ( ! is_object( $term ) ) {
$term = get_term( $term, $taxonomy );
if ( is_wp_error( $term ) ) {
return $term;
}
$use_id = true;
}
// Don't recurse if we've already identified the term as a child - this indicates a loop.
if ( isset( $ancestors[ $term->term_id ] ) ) {
continue;
}
if ( (int) $term->parent === $term_id ) {
if ( $use_id ) {
$term_list[] = $term->term_id;
} else {
$term_list[] = $term;
}
if ( ! isset( $has_children[ $term->term_id ] ) ) {
continue;
}
$ancestors[ $term->term_id ] = 1;
$children = _get_term_children( $term->term_id, $terms, $taxonomy, $ancestors );
if ( $children ) {
$term_list = array_merge( $term_list, $children );
}
}
}
return $term_list;
}
Changelog
Version | Description |
---|---|
2.3.0 | Introduced. |
User Contributed Notes
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