node: When subclassing an existing subclass of EventEmitter, how can I intercept events from the superclass?

Question

I'm attempting to write an extension of a Node library. The library exports a class that extends EventEmitter (class LibClass extends EventEmitter). It is responsible for establishing a websocket connection, and instances of the class fire a "ready" event (with no arguments) when the connection is established.

I would like to subclass this existing class (class MyClass extends LibClass), and when that "ready" event is emitted from the superclass, I want to hold it until my class performs additional setup, then re-emit it afterwards. Functionally, I want all the methods of LibClass to be on MyClass, but I want to override the behavior of certain events like this.

How would I go about doing something like this? Can it be done via sub-classing, or do I have to hold a reference to a LibClass instance somewhere and repeat all the relevant methods and events in my own class to redirect them to that instance?

Answer 1

As Bergi said in the comments, the solution was to override the emit event like so:

class MyClass extends LibClass {
  constructor() {
    super();
    // ...
  }

  emit(name, ...args) {
    if (name === 'someEvent') {
      // Do custom setup for this event
    }
    // Other events will pass through unmodified
    // When setup is completed, or if the event shouldn't be intercepted:
    super.emit(name, ...args);
  }
}