How to make a request for whether a VK user has allowed him to write messages?

Question

API

In general, there is a problem, there is a web application. If a person has once allowed a notification, we want to remove the widget button.

It is clear that for this you need to make a request about the status: whether this user has allowed it or not.
According to the documentation, I did not understand how to do this using the message_allow event.
It says:

In the Callback API and the Bots Longpoll API, the message_allow and message_deny events will help you track whether messages from the community are allowed or denied. Please note that you cannot get a list of all users who have allowed messages to the community through the API, you must store and synchronize this list on your side.

So it's not clear how to do this "tracking fact"?

Answer 1

messages.isMessagesFromGroupAllowed