anchor.diff:  
   [source,bash]
   ----
  -clj -m cljs.main -t node -c hello-world.core
  +clj -m cljs.main -t node -o main.js -c hello-world.core
   ----
   
   You can run your file with:
  
positive.code: [source,clojure]
  ----
  (ns hello-world.core
    (:require cljsjs.react))
  
  (println "Hello React!")
  ----
  
  On Linux or OS X:
  
  [source,bash]
  ----
  clj -m cljs.main -c hello-world.core -r
  ----
  
  On Windows:
  
  [source,bash]
  ----
  java -cp cljs.jar:src:react-15.6.1-0.jar -m cljs.main -c hello-world.core -r
  ----
  
  Once the browser launches, check the JavaScript Console, you should see the
  usual React log indicating that React was successfully loaded.
  
negative.code: (println "Hello world!")
  ----
  
  First we declare our namespace. This namespace must correspond to the location
  of the source file. We then print the famous message.
  
  Now that we have a simple program, let's build and run some ClojureScript:
  
  [source,bash]
  ----
  clj -m cljs.main -c hello-world.core -r
  ----
  
  On Windows:
  
  [source,bash]
  ----
  java -cp "cljs.jar;src" -m cljs.main -c hello-world.core -r
  ----
  
  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
  you will be given a REPL prompt.
  
  Change your `src/hello_world/core.cljs` source file to look like the
  following:
  