Disposable email is a service that allows registered users to get an email at a temporary address that expires after a certain amount of time. They are popular on websites where users need to register and are required to subscribe to a newsletter. So, to prevent email mailboxes from filling up with unnecessary emails people basically tend to prefer to use these disposable email services.
In cases where you cannot have these kinds of disposable emails in your application, your need to test for these disposable emails. This is where we use the npm package disposable-email-domains to check for these disposable emails.