anchor.diff:  Let's check that our watch script works:
   
   ----
  -lein trampoline run -m clojure.main watch.clj
  +cljs -m cljs.main -co build.edn -w -c
   ----
   
   You can verify the script works as intended by invoking Node on `main.js`:
  
positive.code: [[babel-transforms]]
  == Babel Transforms
  
  Change your project.clj to the following:
  
  [source,clojure]
  ----
  (defproject hello-es6 "0.1.0-SNAPSHOT"
    :dependencies [[org.clojure/clojure "1.9.0-alpha14"]
                   [org.clojure/clojurescript "1.9.854"]
                   [cljsjs/react "15.4.2-0"]
                   [cljsjs/react-dom "15.4.2-0"]
                   [cljsjs/react-dom-server "15.4.2-0"]
                   [cljsjs/babel-standalone "6.18.1-3"]]
    :jvm-opts ^:replace ["-Xmx1g" "-server"])
  ----
  
  Change your `watch.clj` to look like the following:
  
  [source,clojure]
  ----
  (require '[cljs.build.api :as b])
  (require '[cljsjs.babel-standalone])
  
  (b/watch "src"
    {:output-to    "main.js"
     :output-dir   "out"
     :main         'hello-es6.core
     :target       :nodejs
     :foreign-libs [{:file "src"
                     :module-type :es6
                     :preprocess 'cljsjs.babel-standalone/transform}] ;; CHANGED
     :verbose      true})
  ----
  
  https://github.com/cljsjs/packages/tree/master/babel-standalone[Babel-standalone] package
  
negative.code: touch project.clj
  ----
  
  Create a `build.edn` file with the following contents:
  
  [source,clojure]
  ----
  {:output-to    "main.js"
   :output-dir   "out"
   :main         hello-es6.core
   :target       :nodejs
   :foreign-libs [{:file "src"
                   :module-type :es6}]
   :verbose      true})
  ----
  
  Notice that a `:foreign-libs` entry may now specify a directory for `:file`.
  