Should the function be executed only once when the button is clicked?

Question

Node.js

Here is such a function:

socket.on('add mess', function(data) {
        $all_users.append("<div>"+ data.name +  "</div>");
      });

The user can click on the button many times, but if the message was published once, it will not be repeated again
. How to display it?
What should this function be wrapped in?

Answer 1

The algorithm is this:

1. We move the code that should work out into a separate function, for exampleFunctionName
   
2. At the end of the function we write something like:button.removeEventListener("click", FunctionName)
   
3. We hang the handler on the button:button.addEventListener("click", FunctionName)