Small PHP function to see if a text blob is json or not

isJson.php

    private function isJson($data): bool
    {
        // check that the first character is { or [
        if (in_array(substr($data, 0, 1), ['{', '['])) {
            // if that worked, try to process as json
            // no errors, return true.
            $json = json_decode($data);

            return json_last_error() === JSON_ERROR_NONE;
        }

        return false;
    }