DOM Control with ClojureScript and Enfocus - problem with lein cjsbuild auto

Question

Hi I'm not an experienced developer and am working my way through this great book Living Clojure: An introduction and training plan for developers by Carin Meier

I'd appreciate your help with an issue I'm stuck on in Chapter 7 (Creating Web Applications with Clojure).

It's walked me through the following sections okay:

Creating a Web Server with Compojure
Using JSON with the Cheshire Library and Ring
Using Clojure in Your Browser with ClojureScript
Browser-Connected REPL
Making HTTP Calls with ClojureScript and cljs-http

But in the section...

DOM Control with ClojureScript and Enfocus...

...I've got to the middle of page 130, ("...Save your edits, and your cljsbuild will recompile your ClojureScript...") but the lein cjsbuild auto, which detects the changes, fails on the attempted compile.

These are the various files I've set up

project.clj

(defproject cheshire-cat "0.1.0-SNAPSHOT"
  :description "FIXME: write description"
  :url "http://example.com/FIXME"
  :min-lein-version "2.0.0"
  :dependencies [[org.clojure/clojure "1.10.0"]
                 [compojure "1.6.1"]
                 [ring/ring-defaults "0.3.2"]
                 [ring/ring-json "0.5.0"]
                 [org.clojure/clojurescript "1.10.597"]
                 [cljs-http "0.1.46"]
                 [org.clojure/core.async "0.5.527"]
                 [enfocus "2.1.1"]]
  :plugins [[lein-ring "0.12.5"]
            [lein-cljsbuild "1.1.7"]]
  :ring {:handler cheshire-cat.handler/app}
  :profiles
  {:dev {:dependencies [[javax.servlet/servlet-api "2.5"]
                        [ring/ring-mock "0.4.0"]]}}
  :cljsbuild {
              :builds [{
                        :source-paths ["src-cljs"]
                        :compiler {
                                   :output-to "resources/public/main.js"
                                   :optimizations :whitespace
                                   :pretty-print true}}]})

src / cheshire_cat / handler.clj

(ns cheshire-cat.handler
  (:require [compojure.core :refer :all]
            [compojure.route :as route]
            [ring.middleware.defaults :refer [wrap-defaults site-defaults]]
            [ring.middleware.json :as ring-json]
            [ring.util.response :as rr]))

(defroutes app-routes
  (GET "/" [] "Hello World")
  (GET "/cheshire-cat" [] 
       (rr/response {:name "Cheshire Cat" :status :grinning}))
  (route/not-found "Not Found"))

(def app
  (-> app-routes 
      (ring-json/wrap-json-response)
      (wrap-defaults site-defaults)))

src-cljs / core.cljs

(ns cheshire-cat.core
  (:require-macros [cljs.core.async.macros :refer [go]])
  (:require [clojure.browser.repl :as repl]
            [cljs-http.client :as http]
            [cljs.core.async :refer [<!]]
            [enfocus.core :as ef]))

(defn ^:export init []
  (repl/connect "http://localhost:9000/repl")
  (go
    (let [response (<! (http/get "/cheshire-cat"))
          body (:body response)]
      (ef/at "#cat-name" (ef/content (:name body)))
      (ef/at "#status" (ef/content (:status body))))))

resources / public / cat.html

<!DOCTYPE html>
<html>
  <head>
    <title>Cheshire Cat</title>
  </head>
  <body>
    <div id="cat-name">Name</div>
    <div id="status">Status</div>

    <script type="text/javascript" src="main.js"></script>
    <script type="text/javascript">cheshire_cat.core.init()</script>
  </body>
</html>

Terminal

On one tab, I've started a server on port 3000 using lein ring server

Another tab is watching for changes before compiling ClojureScript using lein cljsbuild auto

It's here that I'm running into trouble. I'll paste the verbose response below. I tried adding a dependency of domina into the project.clj file, but that didn't help so I removed it again.

Many thanks in advance.

Garys-MacBook-Pro:cheshire-cat garyhudson$ lein cljsbuild auto
Watching for changes before compiling ClojureScript...
Compiling ["resources/public/main.js"] from ["src-cljs"]...
WARNING: domina is a single segment namespace at line 1 file:/Users/garyhudson/.m2/repository/domina/domina/1.0.3/domina-1.0.3.jar!/domina.cljs
WARNING: Protocol DomContent is overwriting function nodes in file file:/Users/garyhudson/.m2/repository/domina/domina/1.0.3/domina-1.0.3.jar!/domina.cljs
WARNING: Protocol DomContent is overwriting function single-node in file file:/Users/garyhudson/.m2/repository/domina/domina/1.0.3/domina-1.0.3.jar!/domina.cljs
WARNING: *debug* not declared dynamic and thus is not dynamically rebindable, but its name suggests otherwise. Please either indicate ^:dynamic *debug* or change the name at line 111 file:/Users/garyhudson/.m2/repository/domina/domina/1.0.3/domina-1.0.3.jar!/domina.cljs
WARNING: Use of undeclared Var goog.dom/query at line 15 file:/Users/garyhudson/.m2/repository/domina/domina/1.0.3/domina-1.0.3.jar!/domina/css.cljs
WARNING: Use of undeclared Var goog.dom/query at line 19 file:/Users/garyhudson/.m2/repository/domina/domina/1.0.3/domina-1.0.3.jar!/domina/css.cljs
Compiling ["resources/public/main.js"] failed.
clojure.lang.ExceptionInfo: failed compiling file:target/cljsbuild-compiler-0/enfocus/core.cljs
             compiler.cljc:1717 cljs.compiler$compile_file$fn__3955.invoke
             compiler.cljc:1677 cljs.compiler$compile_file.invokeStatic
             compiler.cljc:1653 cljs.compiler$compile_file.invoke
                closure.clj:653 cljs.closure/compile-file
                closure.clj:631 cljs.closure/compile-file
                closure.clj:727 cljs.closure/fn
                closure.clj:721 cljs.closure/fn
                closure.clj:549 cljs.closure/fn[fn]
                closure.clj:700 cljs.closure/compile-from-jar
                closure.clj:690 cljs.closure/compile-from-jar
                closure.clj:737 cljs.closure/fn
                closure.clj:721 cljs.closure/fn
                closure.clj:549 cljs.closure/fn[fn]
               closure.clj:1088 cljs.closure/compile-sources[fn]
                LazySeq.java:42 clojure.lang.LazySeq.sval
                LazySeq.java:51 clojure.lang.LazySeq.seq
                   Cons.java:39 clojure.lang.Cons.next
                    RT.java:709 clojure.lang.RT.next
                    core.clj:64 clojure.core/next
                  core.clj:3142 clojure.core/dorun
                  core.clj:3148 clojure.core/doall
                  core.clj:3148 clojure.core/doall
               closure.clj:1084 cljs.closure/compile-sources
               closure.clj:1073 cljs.closure/compile-sources
               closure.clj:3012 cljs.closure/build
               closure.clj:2920 cljs.closure/build
                    api.clj:208 cljs.build.api/build
                    api.clj:189 cljs.build.api/build
                    api.clj:195 cljs.build.api/build
                    api.clj:189 cljs.build.api/build
                compiler.clj:61 cljsbuild.compiler/compile-cljs[fn]
                compiler.clj:60 cljsbuild.compiler/compile-cljs
                compiler.clj:48 cljsbuild.compiler/compile-cljs
               compiler.clj:168 cljsbuild.compiler/run-compiler
               compiler.clj:129 cljsbuild.compiler/run-compiler
form-init2776313306215562422.clj:1 user/eval838[fn]
form-init2776313306215562422.clj:1 user/eval838[fn]
                LazySeq.java:42 clojure.lang.LazySeq.sval
                LazySeq.java:51 clojure.lang.LazySeq.seq
                    RT.java:531 clojure.lang.RT.seq
                   core.clj:137 clojure.core/seq
                  core.clj:3133 clojure.core/dorun
                  core.clj:3148 clojure.core/doall
                  core.clj:3148 clojure.core/doall
form-init2776313306215562422.clj:1 user/eval838
form-init2776313306215562422.clj:1 user/eval838
             Compiler.java:7176 clojure.lang.Compiler.eval
             Compiler.java:7166 clojure.lang.Compiler.eval
             Compiler.java:7635 clojure.lang.Compiler.load
             Compiler.java:7573 clojure.lang.Compiler.loadFile
                   main.clj:452 clojure.main/load-script
                   main.clj:454 clojure.main/init-opt
                   main.clj:454 clojure.main/init-opt
                   main.clj:485 clojure.main/initialize
                   main.clj:519 clojure.main/null-opt
                   main.clj:516 clojure.main/null-opt
                   main.clj:598 clojure.main/main
                   main.clj:561 clojure.main/main
                RestFn.java:137 clojure.lang.RestFn.applyTo
                   Var.java:705 clojure.lang.Var.applyTo
                   main.java:37 clojure.main.main
Caused by: clojure.lang.Compiler$CompilerException: Syntax error macroexpanding clojure.core/ns at (enfocus/macros.clj:1:1).
             Compiler.java:6971 clojure.lang.Compiler.checkSpecs
             Compiler.java:6987 clojure.lang.Compiler.macroexpand1
             Compiler.java:7074 clojure.lang.Compiler.macroexpand
             Compiler.java:7160 clojure.lang.Compiler.eval
             Compiler.java:7635 clojure.lang.Compiler.load
                    RT.java:381 clojure.lang.RT.loadResourceScript
                    RT.java:372 clojure.lang.RT.loadResourceScript
                    RT.java:463 clojure.lang.RT.load
                    RT.java:428 clojure.lang.RT.load
                  core.clj:6126 clojure.core/load[fn]
                  core.clj:6125 clojure.core/load
                  core.clj:6109 clojure.core/load
                RestFn.java:408 clojure.lang.RestFn.invoke
                  core.clj:5908 clojure.core/load-one
                  core.clj:5903 clojure.core/load-one
                  core.clj:5948 clojure.core/load-lib[fn]
                  core.clj:5947 clojure.core/load-lib
                  core.clj:5928 clojure.core/load-lib
                RestFn.java:142 clojure.lang.RestFn.applyTo
                   core.clj:667 clojure.core/apply
                  core.clj:5985 clojure.core/load-libs
                  core.clj:5969 clojure.core/load-libs
                RestFn.java:137 clojure.lang.RestFn.applyTo
                   core.clj:667 clojure.core/apply
                  core.clj:6007 clojure.core/require
                  core.clj:6007 clojure.core/require
                RestFn.java:408 clojure.lang.RestFn.invoke
             analyzer.cljc:4106 cljs.analyzer$ns_side_effects$fn__2653.invoke
             analyzer.cljc:4105 cljs.analyzer$ns_side_effects.invokeStatic
             analyzer.cljc:4077 cljs.analyzer$ns_side_effects.invoke
             analyzer.cljc:4201 cljs.analyzer$analyze_STAR_$fn__2706.invoke
      PersistentVector.java:343 clojure.lang.PersistentVector.reduce
                  core.clj:6827 clojure.core/reduce
                  core.clj:6810 clojure.core/reduce
             analyzer.cljc:4201 cljs.analyzer$analyze_STAR_.invokeStatic
             analyzer.cljc:4191 cljs.analyzer$analyze_STAR_.invoke
             analyzer.cljc:4220 cljs.analyzer$analyze.invokeStatic
             analyzer.cljc:4203 cljs.analyzer$analyze.invoke
             compiler.cljc:1535 cljs.compiler$emit_source.invokeStatic
             compiler.cljc:1508 cljs.compiler$emit_source.invoke
             compiler.cljc:1620 cljs.compiler$compile_file_STAR_$fn__3924.invoke
             compiler.cljc:1428 cljs.compiler$with_core_cljs.invokeStatic
             compiler.cljc:1417 cljs.compiler$with_core_cljs.invoke
             compiler.cljc:1604 cljs.compiler$compile_file_STAR_.invokeStatic
             compiler.cljc:1597 cljs.compiler$compile_file_STAR_.invoke
             compiler.cljc:1702 cljs.compiler$compile_file$fn__3955.invoke
Caused by: clojure.lang.ExceptionInfo: Call to clojure.core/ns did not conform to spec.
                  alpha.clj:705 clojure.spec.alpha/macroexpand-check
                  alpha.clj:697 clojure.spec.alpha/macroexpand-check
                   AFn.java:156 clojure.lang.AFn.applyToHelper
                   AFn.java:144 clojure.lang.AFn.applyTo
                   Var.java:705 clojure.lang.Var.applyTo
             Compiler.java:6969 clojure.lang.Compiler.checkSpecs

I'd assume this book is not free. You are linking to what seems to be the full version of the book there. — cfrick
@cfrick thanks for the github link. Regarding the book, I did buy it from Amazon and have it on my Kindle. I chanced upon the link to the PDF when writing up my question, and included it to make it easier for people to understand where I was coming from. I don't like piracy (if that is what it is) - should I edit my question to remove the link? — garyfhudson
Yes, IMHO it's what people call "piracy". And it even might fall back on you, if the file is watermarked. — cfrick
Cool, I've removed the link to the pdf from the question, @cfrick. Thanks for your feedback — garyfhudson

Alan Thompson Alan Thompson · Accepted Answer · 2019-11-26T22:49:44

Here is the clue you need:

Caused by: clojure.lang.Compiler$CompilerException: Syntax error
           macroexpanding clojure.core/ns at (enfocus/macros.clj:1:1).
....
Caused by: clojure.lang.ExceptionInfo: Call to clojure.core/ns did
           not conform to spec.

So it is a problem in the enfocus library, not your code.

IMHO the enfocus library is a bit old these days. I think you would be better served using the figwheel.main lib for the CLJS code: https://figwheel.org/

Note that this is basically Figwheel 2.0, but under a new name. It is much better than the original Figwheel.

Go through the tutorial at figwheel.org, and build your CLJS code in a separate project directory from your back-end code.

Also, be sure to use the Clojure CLI/Deps to build the CLJS project (i.e. not Leiningen). CLI/Deps is much easier to use for ClojureScript projects than Leiningen.

DOM Control with ClojureScript and Enfocus - problem with lein cjsbuild auto

1 Answers