ClojureScript

Native executables

This guide illustrates how to produce native executables from ClojureScript source. The basic idea is to produce a JavaScript file using the ClojureScript compiler, and then use a Node.js tool called nexe to compile that into an executable. The resulting file can be run without requiring a node install on the target machine, which can be handy.

nexe works by compiling the v8 engine into an exe that also contains your Javascript. So, strictly speaking, your program itself is not being compiled ahead of time. But if what you’re after is the packaging convenience of an EXE, this is still pretty handy.

Setup:

# Install node and nexe
brew install node
npm install nexe -g

Make a little hello world file:

mkdir -p /tmp/nexe-test/src
cd /tmp/nexe-test
cat > src/hello.cljs <<EOF
(ns hello)
(enable-console-print!)
(println "Hello world!")
EOF

Fire up a REPL and compile the ClojureScript:

wget https://github.com/clojure/clojurescript/releases/download/r1.9.293/cljs.jar
java -cp cljs.jar clojure.main <<EOF
(require 'cljs.build.api)
(cljs.build.api/build "src" {:optimizations :advanced :output-to "out/main.js"})
EOF

Use nexe to compile the js into a native exe. This will take a while the first time, but will be reasonably fast for subsequent runs:

nexe -i out/main.js -o hello.exe

# Run it
time ./hello.exe

# It's reasonably fast:
# Hello world!
#
# real   	0m0.095s
# user   	0m0.070s
# sys    	0m0.025s

Enjoy!

Original author: Craig Andera