Tuesday, August 31, 2021

Component Driven ClojureScript with Storybook

Component Driven?

Start small. Develop components in isolation. Don’t forget to pause & reflect on the code you’ve written. Can it be split into several small components?

✨ When you’re ready, combine your components to create features.

✨ Add the features to a view.

✨ Add the view to your app.

You can read more about Component Driven User Interfaces here.


I’ve just begun to use Storybook and currently learning about it. What I especially like so far, is that the tool encourages you to write UI components that are independent … and functional?

This makes it possible to develop user interfaces in isolation. Just pass data and actions as parameters into your components. Keep it simple. This way of working reminds me a lot of Polylith, an architecture I have used in backend focused Clojure projects and that I enjoy a lot.

ClojureScript & Storybook?

You will find a fully working example in this repo. I have added Storybook to a ClojureScript web app, using shadow-cljs, with additional npm scripts located in package.json.

Update: a new version of shadow-cljs supports ns-regexp for the npm-module target. No need to manually add new stories!

The code in my GitHub repo is a continuation of the work I’ve described in an earlier post, about combining shadow-cljs with Webpack and AWS Amplify.

The Clojure Interactive REPL and Storybook working well together.

No JavaScript quirks?

Well, yeah some. The JavaScript ecosystem is evolving fast, tools are updated with breaking changes and sometimes that causes compatibility issues. In this case it is Storybook and Webpack 5. But I have solved it with a few extra rows of configuration. Don’t worry.

An example of a Storybook story written in ClojureScript

Have a look at the fully working example at GitHub.

Many thanks to Shaolang Ai, that wrote this blog post about shadow-cljs and Storybook that I’ve learned a lot from.

Top photo by Etienne Girardet on Unsplash

Sunday, August 29, 2021

Hey Webpack, Hey ClojureScript

✅ ClojureScript is great.

✅ AWS Amplify is great.

🤔 Why are there errors in my browser console?

ClojureScript. Amplified.

Some time ago, I decided to give AWS Amplify a try for a new project. With Amplify, you can quickly create and deploy web apps and AWS backend services by using your command line.

Even though the Amplify code examples and docs are all about JavaScript, I wasn't too keen on abandoning my favorite REPL powered language: Clojure. 🤩

So, I decided to combine two great things: AWS Amplify & ClojureScript!

Amplifed, yes. But with 🔔.

I have learned a lot from this blog post by Robert J Berger about how to setup AWS Amplify with ClojureScript. New versions of the AWS Amplify libraries are released regurarly. The current Major version include breaking changes that probably will cause ClojureScript web apps to raise errors and stop working.

Until recently, I have had to rollback updates and use earlier versions of the Amplify libraries. Nothing wrong with that. But my inner Alarm Bells have been ringing constantly since noticing the word legacy in the official Amplify docs for those library versions (the aws-amplify-react library and the Amplify Auth feature in particular).

The newer Amplify libraries rely on Webpack specific features under the hood. The example setup described in the official Amplify docs include using react-scripts, that (if I'm not mistaking) will package code with Webpack. That kind of setup is not supported by shadow-cljs, a tool that is very common in ClojureScript projects.

Breaking things

In addition to being stuck using legacy code, the app will break each time I add a third party library from npm. I have learned that it is caused by not having a fixed version for amplify libraries defined in my package.json file. A quick fix is to set all AWS Amplify libraries to a fixed version and use that one forever. A version that is becoming more legacy for each day. 🔔🔔🔔

Fix the broken things

The main issue with AWS Amplify libraries, ClojureScript and shadow-cljs is described in this GitHub thread. There is also a suggested solution hinted by Thomas Heller, the creator of shadow-cljs.

A solution: shadow-cljs & Webpack working together

I have created an example app using AWS Amplify and ClojureScript in this repo. Here, shadow-cljs will only create a target JavaScript file containing requires to all of the third party JavaScript dependencies.

Webpack will use that target to create a JavaScript bundle. In a continuous deploy environment, this can easily be automated by executing two scripts instead of one (the shadow-cljs build and webpack).

This solution makes it possible to use the very latest versions of the AWS Amplify libraries, without any css quirks or being forced to use legacy code. Hey Webpack, Hey ClojureScript!

Nowadays, my inner alarm bells are nice & quiet.

Photo by Kamil Pietrzak on Unsplash