Parse-server custom response messages

I have a project where it uses Parse-server 2.8.1 version. This was previously communicated with mLab and with the current migration to MongoDBAtlas, we have to update the parse-server version to the latest. I have seen there was a migrating doc. But there is a part which I not getting yet. How to set custom response messages. For example
if (users.length > 0){
message:‘Screen name has already been taken.’
} else {
message:‘Screen name available.’
How to convert this to support the parse-server latest version. This is a must since mobile apps are communicating with the server, depending on these status values and the message. Appreciate your time… Thank u.

I’ve already answered you over StackOverflow. Please avoid duplicated posts.

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