We've covered a lot of ground in the chapter, so let's retrace our steps a bit before moving on.

One of the most important things I want you to take away from this chapter is how data is sent from the server to the client. We've used two different methods here: first, we use a server-side template to put them into the HTML response and send them as part of that. Secondly, we use fetch commands from the client and create a completely separate HTTP request for that data. The advantage of the first method is that individual "chunks" of data don't have their own HTTP headers; also, since they're part of the initial request, the user will never wait for data while using the application. The advantage of the second method is that we never load more data than we need to from the server; when we need it, it's easy to request it. This is especially important in an application like this one, where a single user could have hundreds of posted photos over time, and people are likely to follow...