Angular 'this' reference undefined within Set function each

That’s different from what I remember, because now your code is passing this function:

          e.subject.each( function(node) {
              console.log('In loop');
              console.log('Node: ' + node.data['text']);
              this.nodeHandler(node);
          }

But that too is very wrong, because using this inside a function implies that function is being used as a method on an object. Yet you should have no intention of passing a method to the Set.each method.

I think you could fix that by using an arrow function there too.

Again, these problems are being caused by JavaScript, not Angular or GoJS.