PHP split text into 2 parts based on length

truncate.php

<?php

function truncate($full, $length) 
{
    $length = abs((int)$length);

    if (strlen($full) > $length) {
        $first = preg_replace("/^(.{1,$length})(\s.*|$)/s", '\\1', $full);
        $second = substr($full, strlen($first));
    }

    return [
        'first' => $first,
        'second' => $second
    ];
}