PHP: Insert item into an array

insert-into-array.php

<?php

/**
 * Inserts an item into an array.
 *
 * @param array $array    The array to insert into.
 * @param mixed $key      The array key to insert the item at, either before or after.
 * @param mixed $new_key  The new array key.
 * @param mixed $new_item The new item to insert.
 * @param bool  $before   Insert before or after?
 * @return array
 */
function insert_into_array( $array, $key, $new_key, $new_item, $before = true ) {

	if ( ! is_array( $array ) || empty( $key ) || empty( $new_key ) ) {
		return $array;
	}

	if ( ! array_key_exists( $key, $array ) ) {
		$array[ $new_key ] = $new_item;
		return $array;
	}

	$new_array = [];

	foreach ( array_keys( $array ) as $array_key ) {

		if ( $before && $array_key == $key ) {
			$new_array[ $new_key ] = $new_item;
		}

		$new_array[ $array_key ] = $array[ $array_key ];

		if ( ! $before && $array_key === $key ) {
			$new_array[ $new_key ] = $new_item;
		}
	}

	return $new_array;
}