str_contains() was introduced in PHP8. This is a polyfill for PHP7 or lower.

str_contains.php

<?php
if (!function_exists('str_contains')) {
    /**
     * Check if substring is contained in string
     *
     * @param $haystack
     * @param $needle
     *
     * @return bool
     */
    function str_contains($haystack, $needle)
    {
        return (strpos($haystack, $needle) !== false);
    }
}

Thank you!