WhatsApp is developing message reaction or responses similar to Instagram and Twitter. Message responses will be to improve the functionality of the instant messaging service. As per un officail source, WhatsApp is presently testing the message response function internally.
This will be similar to reactions on Twitter, Instagram, and Facebook Messenger, where users may simply react with an expression (emoji) . WhatsApp is currently working on on it which would allow users to use WhatsApp on different devices without having to check in on their cellphones each time.