Ep 116: The Main Focus

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Each week, we discuss a different topic about Clojure and functional programming.

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This week, the topic is: "frontend matters". We turn our attention to the frontend, and our eyes burn from the complexity.

Our discussion includes:

Selected quotes

You don't usually go into a code base just to browse it, or just to have fun. You go there with a purpose. You need to work. You need to get something done fast.

We like rich frontends. We're able to do a lot more interactivity. There's less interruption when the page has to load. There are a lot of advantages to SPAs.

With a SPA, it's really, really fast to switch between everything. It feels almost instantaneous because there is almost nothing to load each time.

The counterpart is that a SPA is more sophisticated, so it ends up being more complicated. It's almost like a process that's running continuously. There's more code that's present in a SPA than any individual page load.

From the browsers point of view, the "main" is the markup, and you have to tell it to run some code.

It's just one blob of code to the browser. You can't look at that code because it's transpiled, minified JavaScript.

I do think it's interesting that we've gotten several minutes into this episode, and we're still talking about how things get made into the final sausage. It's reflective of how much effort it takes to set up the JavaScript ecosystem.

We make a "main.cljs" file, and that is the top of the application. It's a signpost. "Hey! Hey! Look here first!"

The tab's not going to go away, so all we need to do is start up all the event listeners because JavaScript is a very event-driven language.

I want "main" to be a table of contents of everything that matters in the app: the views, the routes, the URLs, browser hooks, web sockets, etc.

The worst kind of "main" is no "main" at all. There are frameworks where you make a whole bunch of separate files for each of your routes.

I love how many times we said the word "react" in this episode. It's all very event driven. That's just the model of the whole browser. It's the water that you swim in, so you must swim the right way in order for the application to succeed.

Reactive cycle

User Interaction → Event → Callback → Reactive Model → Re-Render

Kinds of frontend components