wpseek.com
A WordPress-centric search engine for devs and theme authors

function term_exists( $term, $taxonomy = '', $parent_term = null ) {
	global $_wp_suspend_cache_invalidation;

	if ( null === $term ) {
		return null;
	}

	$defaults = array(
		'get'                    => 'all',
		'fields'                 => 'ids',
		'number'                 => 1,
		'update_term_meta_cache' => false,
		'order'                  => 'ASC',
		'orderby'                => 'term_id',
		'suppress_filter'        => true,
	);

	// Ensure that while importing, queries are not cached.
	if ( ! empty( $_wp_suspend_cache_invalidation ) ) {
		$defaults['cache_results'] = false;
	}

	if ( ! empty( $taxonomy ) ) {
		$defaults['taxonomy'] = $taxonomy;
		$defaults['fields']   = 'all';
	}

	/**
	 * Filters default query arguments for checking if a term exists.
	 *
	 * @since 6.0.0
	 *
	 * @param array      $defaults    An array of arguments passed to get_terms().
	 * @param int|string $term        The term to check. Accepts term ID, slug, or name.
	 * @param string     $taxonomy    The taxonomy name to use. An empty string indicates
	 *                                the search is against all taxonomies.
	 * @param int|null   $parent_term ID of parent term under which to confine the exists search.
	 *                                Null indicates the search is unconfined.
	 */
	$defaults = apply_filters( 'term_exists_default_query_args', $defaults, $term, $taxonomy, $parent_term );

	if ( is_int( $term ) ) {
		if ( 0 === $term ) {
			return 0;
		}
		$args  = wp_parse_args( array( 'include' => array( $term ) ), $defaults );
		$terms = get_terms( $args );
	} else {
		$term = trim( wp_unslash( $term ) );
		if ( '' === $term ) {
			return null;
		}

		if ( ! empty( $taxonomy ) && is_numeric( $parent_term ) ) {
			$defaults['parent'] = (int) $parent_term;
		}

		$args  = wp_parse_args( array( 'slug' => sanitize_title( $term ) ), $defaults );
		$terms = get_terms( $args );
		if ( empty( $terms ) || is_wp_error( $terms ) ) {
			$args  = wp_parse_args( array( 'name' => $term ), $defaults );
			$terms = get_terms( $args );
		}
	}

	if ( empty( $terms ) || is_wp_error( $terms ) ) {
		return null;
	}

	$_term = array_shift( $terms );

	if ( ! empty( $taxonomy ) ) {
		return array(
			'term_id'          => (string) $_term->term_id,
			'term_taxonomy_id' => (string) $_term->term_taxonomy_id,
		);
	}

	return (string) $_term;
}