What is snapchat typing notification but no message?

When someone is typing a message to you on Snapchat, you will see a notification indicating that they are typing. However, if they ultimately do not send a message, you will not receive any further notification or indication that they were typing beforehand. The typing notification is a way for Snapchat to let you know when someone is actively composing a message to you, but it does not provide any additional information beyond that.