title: How to make an angular custom validator work only on submission?
body: <p>I developed a login component using the Angular-8 <strong>reactive form</strong> concept. I have asynchronous validations like empty fields, invalid emails. these validations should be asynchronous. But I have two custom validators like <strong>is-user-exist</strong>, <strong>is-password-match-user</strong>. These two validators should be only validated if user clicks submit. How to have a reactive form validator to <strong>check these two validators alone on submitting</strong> and other validations asynchronously.</p>