Hi Srigi thanx for your review. You are right, to be sure that the iframe content is also loaded and ready to receive messages, the onLoad event makes sense. I updated the point 3 accordingly.
Your second point is a good catch! A typo from my side :-) I experimented with the ES7 functions and forgot the colons somehow. These bindings make really no sense there since handleFrameTasks function doesn’t use any context data (this).
But if the context were needed, I would put the colons into constructor. This could work.
this.handleFrameTasks = ::this.handleFrameTasks;