Creating a desktop app with Atom Shell and ClojureScript

Atom Shell gives you a way to create a desktop(ish) web application which can access your local OS via the Node.js environment and the npm module ecosystem.

This working example presents a way to use all this power with ClojureScript.

There's some Javascript left: bootstrap.js. This file doesn't require much changes so I see no problem with leaving it as it is.

The rest of the stuff is ClojureScript, and it's in src/example/core.js. The UI (not much of that :)) uses Reagent.

There are two types of dependencies here:

• Node modules (installed via apm)
• ClojureScript modules (installed via leiningen)

Using Reagent to render HTML demonstrates that leiningen dependencies are working, and using the walk module shows how to use npm modules.

Installing Atom Shell

You can get pre-built binaries from here.

Installing native node modules

To depend on native Node modules you should use apm. How do you install the apm package manager? Well, with npm package manager of course :) npm install apm (I used the npm 2.7.1 which comes with io.js 1.6.1)

In our example we depend on the native node module "walk", so let's install it locally to our Atom Shell application directory:

apm install .

Note: do not run apm install , it will not work for Atom Shell app.

Build the app

You need leiningen. Get it from here

Fetch dependencies:

lein deps

To build once, run:

lein cljsbuild once

To build automatically, run:

lein cljsbuild auto

Sometimes you will get nasty "Uncaught Error: goog.require could not find: example.core" errors. Try to delete everything under out/ directory manually and rebuild. Leiningen's clean doesn't do the trick for some reason.

Run the app

cd to this checkout directory, and run Atom in there:

/Applications/Atom.app/Contents/MacOS/Atom .

(the path to Atom is specific to your OS and Atom installation of course)

REPL

There are a few ways to create REPLs with ClojureScript. Unfortunately, almost all of them require running our generated JavaScript via a page served by a web server. With Atom Shell, there's no web server. We are just browsing local files via "file://" Here we can see multiple ways to connect a REPL to browser. The only one of these that works somewhat is the Rhino one:

lein trampoline cljsbuild repl-rhino

And that can't run our Node environment properly. We can't, for example, require a node module and use it since we are inside Rhino/JVM.