trying to do lein expo.clj

gary@gary-macbook:~/dev$ lein new expo expotest
Retrieving expo/lein-template/0.17.1/lein-template-0.17.1.pom from clojars
Retrieving expo/lein-template/0.17.1/lein-template-0.17.1.jar from clojars
Generating fresh Expo project.
README.md contains instructions to get you started.
If you have any questions, you can ask us on Expo slack #clojurescript channel. https://slack.expo.io/
gary@gary-macbook:~/dev$ cd expotest/
gary@gary-macbook:~/dev/expotest$ cat project.clj 
(defproject expotest "0.1.0-SNAPSHOT"
  :description "FIXME: write description"
  :url "http://example.com/FIXME"
  :license {:name "Eclipse Public License"
            :url  "http://www.eclipse.org/legal/epl-v10.html"}
  :dependencies [[org.clojure/clojure "1.9.0-alpha16"]
                 [org.clojure/clojurescript "1.9.542"]
                 [org.clojure/core.async "0.3.442"]
                 [reagent "0.6.1" :exclusions [cljsjs/react cljsjs/react-dom cljsjs/react-dom-server]]
                 [re-frame "0.9.3"]
                 [react-native-externs "0.0.2-SNAPSHOT"]]
  :plugins [[lein-cljsbuild "1.1.4"]
            [lein-figwheel "0.5.10"]]
  :clean-targets ["target/" "main.js"]
  :aliases {"figwheel" ["run" "-m" "user" "--figwheel"]
            "externs" ["do" "clean"
                       ["run" "-m" "externs"]]
            "rebuild-modules" ["run" "-m" "user" "--rebuild-modules"]
            "prod-build" ^{:doc "Recompile code with prod profile."}
            ["externs"
             ["with-profile" "prod" "cljsbuild" "once" "main"]]}
  :profiles {:dev {:dependencies [[figwheel-sidecar "0.5.10"]
                                  [com.cemerick/piggieback "0.2.1"]]
                   :source-paths ["src" "env/dev"]
                   :cljsbuild    {:builds [{:id "main"
                                            :source-paths ["src" "env/dev"]
                                            :figwheel     true
                                            :compiler     {:output-to     "target/not-used.js"
                                                           :main          "env.main"
                                                           :output-dir    "target"
                                                           :optimizations :none}}]}
                   :repl-options {:nrepl-middleware [cemerick.piggieback/wrap-cljs-repl]}}
             :prod {:cljsbuild {:builds [{:id "main"
                                          :source-paths ["src" "env/prod"]
                                          :compiler     {:output-to     "main.js"
                                                         :main          "env.main"
                                                         :output-dir    "target"
                                                         :static-fns    true
                                                         :externs       ["js/externs.js"]
                                                         :parallel-build     true
                                                         :optimize-constants true
                                                         :optimizations :advanced
                                                         :closure-defines {"goog.DEBUG" false}}}]}}})
gary@gary-macbook:~/dev/expotest$ cat build.boot 
(set-env!
 :source-paths   #{"src" "env/dev"}
 :dependencies '[[ajchemist/boot-figwheel "0.5.4-6" :scope "test"] ;; latest release
                 [org.clojure/tools.nrepl "0.2.12" :scope "test"]
                 [com.cemerick/piggieback "0.2.1" :scope "test"]
                 [figwheel-sidecar "0.5.4-7" :scope "test"]
                 [react-native-externs "0.0.2-SNAPSHOT" :scope "test"]

                 [org.clojure/clojure "1.9.0-alpha16"]
                 [org.clojure/clojurescript "1.9.542"]
                 [org.clojure/core.async "0.3.442"]
                 [reagent "0.6.1" :exclusions [cljsjs/react cljsjs/react-dom cljsjs/react-dom-server]]
                 [re-frame "0.9.3"]])

(require
 '[boot-figwheel :refer [figwheel cljs-repl]]
 '[cljs.build.api :as b]
 '[user :as user]
 '[externs :as externs])

(require 'boot.repl)
(swap! boot.repl/*default-middleware*
       conj 'cemerick.piggieback/wrap-cljs-repl)

(deftask dev
  "boot dev, then input (cljs-repl)"
  []
  (user/prepare)

  (comp
   (figwheel
    :build-ids  ["main"]
    :all-builds [{:id "main"
                  :source-paths ["src" "env/dev"]
                  :figwheel true
                  :compiler     {:output-to     "not-used.js"
                                 :main          "env.main"
                                 :optimizations :none
                                 :output-dir    "."}}]
    :figwheel-options {:open-file-command "emacsclient"
                       :validate-config false})
   (repl)))

(deftask prod
  []
  (externs/-main)

  (println "Start to compile clojurescript ...")
  (let [start (System/nanoTime)]
    (b/build ["src" "env/prod"]
             {:output-to     "main.js"
              :main          "env.main"
              :output-dir    "target"
              :static-fns    true
              :externs       ["js/externs.js"]
              :parallel-build     true
              :optimize-constants true
              :optimizations :advanced
              :closure-defines {"goog.DEBUG" false}})
    (println "... done. Elapsed" (/ (- (System/nanoTime) start) 1e9) "seconds")))