anchor.diff:  java -cp "cljs.jar;src" -m cljs.main -c hello-world.core -r
   ----
   
  +`-m`, which is short for `--main` invokes a Clojure function, in this case
  +`cljs.main`. The `cljs.main` function supports a variety of command line
  +arguments to specify common tasks. We're using `-c` for `--compile` to specify
  +that we want to compile the `hello-world.core` name space. This is followed by
  +`-r` for `--repl` to say that want a REPL to start immediately when compilation
  +completes.
  +
   Your default web browser will open to a page that looks like the following:
   
   After a couple of seconds you will see `Hello world!` print at the terminal and
  
positive.code: npm install source-map-support
  ----
  
  Let's build your Node project:
  
  [source,bash]
  ----
  
negative.code: java -cp "cljs.jar;src" -m cljs.main -s
  ----
  
  `-s` is for `--serve`. This command does not start REPL, so a browser window will not be automatically
  opened. Navigate to http://localhost:9000 using your favorite browser. Check the
  JavaScript Console, you should see `Hello world!` printed. The build in web
  server gzips JavaScript. Check your browser network tab and you should be able
  