Wow – dangerous title, right? Our grasp of what is essential certainly changes alongside our understanding of the problems which we are trying to solve. So I won’t lie to you – what I thought was essential a year ago was woefully incomplete, as I’m sure what I’m about to write will seem to me six months down the road. So – this post is a snapshot in time of a few of the things I’ve found to be critical for successfully applying client-side messaging patterns in JavaScript.