Now the ISBNs are stored how the used write them in the input field. That mean you can have in your database ISBN in lot of different format.
I think it's better to save ISBNs without any alphanumeric character. It can then be formatted when displayed. We can also change the database field in INT.
I think it's a bug because it make the data almost impossible to query.
Active
1.0
Code
Not all content is available!
It's likely this issue predates Contrib.social: some issue and comment data are missing.
This looks like to be fixed as part of #2878502: D8 Version → . Upon save, any characters that are not a number or letter, are removed:
public function cleanup(string $isbn): string {
return preg_replace('/[^0-9a-zA-Z]/', '', $isbn);
}