This is a Leiningen plugin that makes it quick and easy to automatically compile
your ClojureScript code into Javascript whenever you modify it. It's simple
to install and allows you to configure the ClojureScript compiler from within your
project.clj file.
Beyond basic compiler support, lein-cljsbuild can optionally help with a few other things:
The latest version of lein-cljsbuild is 1.1.8.
See the release notes here.
Note that cljsbuild crossovers are deprecated, and will be removed eventually. You should never use them. Please use either reader conditionals (available in Clojure >= 1.7.0-beta2 and ClojureScript >= 0.0-3255), or cljx to target both Clojure and ClojureScript from the same codebase.
If you are using ClojureScript >= 1.7.170 you need to use a lein-cljsbuild version >= 1.1.1.
The lein-cljsbuild plugin works with
Leiningen
version 2.1.2 or higher.
You can install the plugin by adding lein-cljsbuild to your project.clj
file in the :plugins section:
(defproject lein-cljsbuild-example "1.2.3"
:plugins [[lein-cljsbuild "1.1.8"]])In addition, you should add an explicit ClojureScript dependency to your project using the ClojureScript version you want to use:
:dependencies [[org.clojure/clojurescript "1.9.521"]]lein-cljsbuild will add a dependency to your project if it doesn't already
contain one, but that functionality will not remain for long. The latest
version of lein-cljsbuild currently requires a minimum of ClojureScript
0.0-3211.
See the example-projects directory for a couple of simple examples of how to use lein-cljsbuild. The simple project shows a dead-simple "compile only" configuration, which is a good place to start. The advanced project contains examples of how to use the extended features of the plugin.
For an exhaustive list of all options supported by lein-cljsbuild, see the sample.project.clj file. For a list of options that can be passed to the ClojureScript compiler have a look at the ClojureScript Compiler Options site.
The lein-cljsbuild configuration is specified under the :cljsbuild section
of your project.clj file. A simple project might look like this:
(defproject lein-cljsbuild-example "1.2.3"
:plugins [[lein-cljsbuild "1.1.8"]]
:cljsbuild {
:builds [{
; The path to the top-level ClojureScript source directory:
:source-paths ["src-cljs"]
; The standard ClojureScript compiler options:
; (See the ClojureScript compiler documentation for details.)
:compiler {
:output-to "war/javascripts/main.js" ; default: target/cljsbuild-main.js
:optimizations :whitespace
:pretty-print true}}]})Once the plugin is installed, you can build the ClojureScript once:
$ lein cljsbuild once
Or you can have lein-cljsbuild watch your source files for changes and automatically rebuild them. This is recommended for development, as it avoids the time-consuming JVM startup for each build:
$ lein cljsbuild auto
Assuming you have configured cljsbuild to emit compiler output to one of
Leiningen's :clean-targets (which includes ./target by default), running
lein clean will delete all of the JavaScript and ClojureScript files that lein-cljsbuild
generates during compilation.
Colors are a big deal when reading ClojureScript compiler output, but Windows consoles don't support ANSI color codes. This limitation is commonly corrected by installing ANSICON:
- Download and unzip ANSICON anywhere.
- Open a command prompt (Run as administrator).
- Navigate to the unzipped folder.
- cd x86 or x64 (depending on whether you have 32-bit or 64-bit machine, respectively)
- Run
ansicon -ito install.
Afterwards, you should get colored output from all future console sessions that use ANSI color codes.
Some common lein-cljsbuild tasks can hook into the main Leiningen tasks to enable ClojureScript support in each of them. The following tasks are supported:
$ lein compile
$ lein test
$ lein jar
To enable ClojureScript support for these tasks, add the following entry to your project configuration:
:hooks [leiningen.cljsbuild]Note that by default the lein jar task does not package your ClojureScript
code in the JAR file. This feature needs to be explicitly enabled by adding
the following entry to each of the :builds that you want included in the
JAR file. lein uberjar derives its behavior from lein jar and will include
the ClojureScript as well if enabled.
:jar trueDebug Note: There is a known issue (#366) where the
lein uberjartask fails to build when using hooks and a cljsbuild configuration within an:uberjarprofile. Instead of hooks, you can use:prep-tasksas an alternative::prep-tasks ["compile" ["cljsbuild" "once"]]
If the :builds sequence contains more than one map lein-cljsbuild
will treat each map as a separate ClojureScript compiler configuration,
and will build all of them in parallel:
(defproject lein-cljsbuild-example "1.2.3"
:plugins [[lein-cljsbuild "1.1.8"]]
:cljsbuild {
:builds [
{:source-paths ["src-cljs-main"]
:compiler {:output-to "main.js"}}
{:source-paths ["src-cljs-other"]
:compiler {:output-to "other.js"}}]})This is extremely convenient for doing library development in ClojureScript. This allows cljsbuild to compile in all four optimization levels at once, for easier testing, or to compile a test suite alongside the library code.
You can optionally assign an ID to a build configuration and build only that one:
(defproject lein-cljsbuild-example "1.2.3"
:plugins [[lein-cljsbuild "1.1.8"]]
:cljsbuild {
:builds [
{:source-paths ["src-cljs-main"]
:compiler {:output-to "main.js"}}
{:id "other"
:source-paths ["src-cljs-other"]
:compiler {:output-to "other.js"}}]})$ lein cljsbuild auto other
If you want IDs for all of your build configurations, you can specify them as a map instead of a vector:
(defproject lein-cljsbuild-example "1.2.3"
:plugins [[lein-cljsbuild "1.1.8"]]
:cljsbuild {
:builds {
:main
{:source-paths ["src-cljs-main"]
:compiler {:output-to "main.js"}}
:other
{:source-paths ["src-cljs-other"]
:compiler {:output-to "other.js"}}}})You can also build multiple configurations at once:
$ lein cljsbuild auto main other
See the example-projects/advanced directory for a working example of a project that uses this feature.
Lein-cljsbuild has built-in support for launching ClojureScript REPLs in a variety of ways. See the REPL documentation for more details.
Lein-cljsbuild has built-in support for running external ClojureScript test processes. See the testing documentation for more details.
You can place custom warning handlers for the ClojureScript compiler under the :warning-handlers key. The value should be a vector of either 1.) fully-qualified symbols that resolve to your custom handler, or 2.) anonymous functions that will get eval'd at project build-time.
(defproject lein-cljsbuild-example "1.2.3"
:plugins [[lein-cljsbuild "1.0.4"]]
:cljsbuild {
:builds {:id "example"
:compiler {}
:warning-handlers [my.ns/custom-warning-handler ;; Fully-qualified symbol
;; Custom function (to be evaluated at project build-time)
(fn [warning-type env extra]
(when-let [s (cljs.analyzer/error-message warning-type extra)]
(binding [*out* *err*]
(cljs.analyzer/message env s))))]}})After configuring lein-cljsbuild, lein deps will fetch a known-good version of the ClojureScript compiler.
You can use a different version of the compiler via a local clone of the ClojureScript git repository.
See the wiki for details.
Source Copyright © Evan Mezeske, 2011-2013. Released under the Eclipse Public License - v 1.0. See the file COPYING.
A big thank you to all contributors who help to make this project better.
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