Figwheel builds your ClojureScript code and hot loads it into the browser as you are coding!
- A 6 minute flappy bird demo of figwheel
- A more detailed 45 minute talk on Figwheel given at ClojureWest 2015.
- An introductory blog post.
Live code reloading
If you write reloadable code, figwheel can facilitate automated live interactive programming. Every time you save your ClojureScript source file, the changes are sent to the browser so that you can see the effects of modifying your code in real time.
Heads up display
Figwheel has a non-intrusive heads up display that gives you feedback on how well your project is compiling. By writing a shell script you can click on files in the heads up display and they will open in your editor!
Built-in ClojureScript REPL
When you launch figwheel it not only starts a live building/reloading process but it also optionally launches a CLJS REPL into your running application. This REPL shares compilation information with the figwheel builder, so as you change your code the REPL is also aware of the code changes. The REPL also has some special built-in control functions that allow you to control the auto-building process and execute various build tasks without having to stop and rerun lein-figwheel.
Figwheel's connection is fairly robust with sessions that can last for days through multiple OS sleeps. You can also use figwheel like a REPL if you are OK with using
Figwheel broadcasts changes to all connected clients. This means you can see code and CSS changes take place in real time on your phone and in your laptop browser simultaneously.
Figwheel will not load a file that has not been required. It will also respond well to new requirements and dependency tree changes.
Calculates minimal reload set
Figwheel does its best to only reload what needs to be reloaded. This minimizes the surface area of dynamically reloaded code, which in turn should increase the stability of the client environment.
Doesn't load code that is generating warnings
If your ClojureScript code is generating compiler warnings Figwheel won't load it. This, again, is very helpful in keeping the client environment stable. This behavior is optional and can be turned off.
Static file server
The inclusion of a static file server allows you to get a decent ClojureScript development environment up and running quickly. For convenience there is a
:ring-handler option so you can load a Clojure ring handler into the figwheel server.