cljb

Browser support for ClojureScript.

What is cljb?

cljb is a tiny JavaScript shim that allows you to run ClojureScript directly in the browser without the need for local build tools.

Why is it called cljb?

cljb is short for "clojure in the browser".

Why is cljb relevant?

I'm not sure it is, but I think it's pretty neat :)

I've always found it strange that compile-to-js languages are your only option for building web apps. A web browser is more than a compilation target - it's is own environment with great support for runtime debugging and interactivity. There's great potential for interactive development but many of us choose to use other languages, libraries and frameworks that shift the development experience from happening within the browser to a hybrid of browser + external tools. I don't think it has to be this way and cljb is a PoC of what an alternative to a JS-only browser could look like.

How do I use it?

You first have to make the cljb runtime available in your web app:

<head>
  ...
  <script src="https://<the-path-to-the-hosted-shim>.js"></script>
  ...
</head>

You then have the option to either include .cljb files just as you would any other .js file in your web app:

<script src="/path/to/my/web_app.cljb"></script>

Or you can inline cljb code just as you would with JS code:

<script type="application/cljb">
  (defn say-hello [name]
    (println "Hello" name))

  (say-hello "Frodo")
</script>

How does it work?

cljb includes the ClojureScript runtime, prebundled using the fantastic Clojure compiler sci, alongside a default set of libraries that I think many web app developers will find useful.

When cljb is included in your web app it will wait for the page to load, find all external and inlined cljb code and execute it within the cljb runtime in the order that it appears on the page.

Bundled libraries

These come pre-bundled with cljb, lmk if you'd like to see another library on this list.

re-frame
reagent

Development

cljb's source code is located under src/ and example code under public/.

Start by running:

bun start

This will auto compile cljb's source code whenever it's edited and start a web server on localhost:3000 that serves the public/ folder.

Navigate to http://localhost:3000 and start playing around.

Looveh / cljb