How to check if the previous message is equal to the next one?

Question

JavaScript

How to check if the previous message is equal to the next one?
I use EASYVK.api, but you can do it on any, I understand

Answer 1

https://vk.com/dev/messages.getHistory - get the latest messages, look for the user's last message among them, check.
Well, or we save the last message from the user in the database / memory.