$ cljsc src '{:optimizations :whitespace :output-dir "out" :output-to "main.js" :source-map "main.js.map"}'ClojureScript now supports HTML source maps so that you can debug
ClojureScript directly in the browser, using the configuration option
:source-map.
:source-map can be either a boolean, or if optimizations are enabled,
a path to a file for the map.
Using the bin/cljsc script herein, you can run something like the
following on the command line, adjusted for your project:
$ cljsc src '{:optimizations :whitespace :output-dir "out" :output-to "main.js" :source-map "main.js.map"}'If you are building using leiningen, a similar section in project.clj
would look something like:
:cljsbuild {
:builds [{:id "main"
:source-paths ["src"]
:compiler {
:output-to "main.js"
:output-dir "out"
:optimizations :none
:source-map true}}]})After compilation, you may then open an HTML file linking to the generated js file in Chrome. Make sure that source maps in Chrome are enabled via the Chrome Developer Tools settings.
Source maps also work with :optimizations set to :none. In this case
the :source-map value doesn’t control file names. So long as the value
is truth-y (cf. the leiningen example above), an individual source map
file will be generated for every ClojureScript source file.
It’s important to note there are some source map option restrictions
when using an :optimizations setting other than :none. In these
cases :output-to, :output-dir, and :source-map must all share the
exact same parent directory. The generated JavaScript file
(:output-to) will contain a line at the end linking it to its source
map like so:
//# sourceMapping=<sourceMapURL>
The sourceMapURL is the :source-map path, relative to :output-to,
since that is how the browser will then resolve it. For example, when
given:
{:output-to "resources/public/js/compiled/main.js"
:output-dir "resources/public/js/compiled"
:optimizations :simple
:source-map "resources/public/js/compiled/main.js.map"}The resulting sourceMapURL will be: main.js.map.
All source files will get copied into :output-dir so that they can be
resolved, however this is not useful in the case where you have a web
server. :source-map-path can be used to define an arbitrary path
prefix. So instead of source map file references resolving to something
like resources/public/js/out you can instead instead specify
:source-map-path "js/out".