How are event handlers hung in JXA (JavaScript for Automation) on macOS?

Question

JavaScript

Hey!
I want to attach a handler to an incoming message from the Messages application. From the documentation, I personally do not understand anything. Only a couple of words are written about the parameters, but what to hang it on and how - no. There is almost no information on handlers on the Internet, and if there is, it does not work. Maybe there are those who know?

Answer 1

A Good Cookbook: JavaScript for Automation Cookbook .
Listen to events via Messages - Preferences - AppleScript handler.
They sort it out on stackoverflow .