Duct Simple ClojureScript Compiler

Integrant methods for compiling ClojureScript using functions from cljs.build.api. Designed for the Duct framework, but can be used in any Integrant configuration.

This compiler supports hot reloading when resumed from a suspended state. When using the :output-to option, it will generate a script that loads dependencies via eval with the sourceURL pragma, which is more efficient than the default document.write method.

Installation

Add the following dependency to your deps.edn file:

org.duct-framework/compiler.cljs.simple {:mvn/version "0.1.1"}

Or to your Leiningen project file:

[org.duct-framework/compiler.cljs.simple "0.1.1"]

Usage

The :duct.compiler.cljs.simple/build key takes the same options as the cljs.build.api function, detailed in the ClojureScript Compiler Options document. It also takes an extra :logger option, which can be connected to a Duct logger.

Here's an example of a typical development build configuration:

{:duct.compiler.cljs.simple/build
 {:asset-path "/js"
  :logger #ig/ref :duct/logger
  :output-dir "target/cljs/js"
  :output-to "target/cljs/js/client.js"
  :optimizations :none
  :preloads [duct.client.repl.simple.preload]
  :main test-project.client}}

The preload adds support for hot reloading and REPL evaluation. This needs to be paired with the :duct.compiler.cljs.simple/server key, which sets up a websocket server for handling reloading on the server side. This is only used while developing.

The :duct.compiler.cljs.simple/server key takes the following options:

• :build - a ref linking to a :duct.compiler.cljs.simple/build key
• :logger - a Duct logger
• :port - the port to run the server on (defaults to 9000)

For example:

{:duct.compiler.cljs.simple/build
 {...}
 :duct.compiler.cljs.simple/server
 {:build #ig/ref :duct.compiler.cljs.simple/build
  :logger #ig/ref :duct/logger}}}

When the system is suspended then resumed, typically via a (reset), any changed files will be sent to the browser to be reloaded in place. Arbitrary ClojureScript may also be sent to the browser using the duct.compiler.cljs.simple/eval-cljs function.

(require '[duct.compiler.cljs.simple :as simple])

(simple/eval-cljs
 (-> system ::simple/server :sessions deref first)
 '(js/console.log "Hello World"))

License

Copyright © 2026 James Reeves

Distributed under the Eclipse Public License either version 1.0 or (at your option) any later version.