In this chapter, first we set up Webpack to produce a separate bundle for the server, then we wrote a simple webapp using Koa 2 that used D3's Voronoi geom to find the nearest airport to a particular latitude/longitude pair. We then upgraded our server app to draw a map using D3 and Canvas, which we then outputted to the user as a PNG via a base64-encoded string.
Wasn't that all really pretty weird, but also kind of fun? Writing server-side code is like that. However, it can also be really rather cathartic after spending a bunch of time doing frontend development, which tends to be really finicky due to having to support so many devices. Furthermore, although purely client-side single-page applications were popular for a while, webapps are increasingly pre-rendered via a server, then rehydrated once they arrive for the user. It's never been more important for frontend developers to have at least a passable understanding of what's going on behind the scenes.
There's clearly quite a...
