Basic nREPL / cljs compile / cljs repl / figwheel script for use with clj cli command: `clj build.clj TASK`

build.clj

(require '[cljs.build.api :as api]
         '[clojure.string :as string]
         '[figwheel-sidecar.repl-api :as figwheel]
         '[figwheel-sidecar.components.nrepl-server :as figwheel.nrepl])

(def source-dir "src")

(def compiler-config
  {:main          'app.main
   :output-to     "target/app.js"
   :source-map    "target/app.js.map"
   :output-dir    "target/out"
   :optimizations :advanced})

(def dev-config
  (merge compiler-config
         {:optimizations :none
          :source-map    true}))

(def nrepl-options
  {:nrepl-port       7890
   :nrepl-middleware ["cider.nrepl/cider-middleware"
                      "refactor-nrepl.middleware/wrap-refactor"
                      "cemerick.piggieback/wrap-cljs-repl"]})

(def ensure-nrepl-port! #(spit ".nrepl-port" (:nrepl-port nrepl-options)))

(def figwheel-options
  {:figwheel-options nrepl-options
   :all-builds       [{:id           "dev"
                       :figwheel     true
                       :source-paths [source-dir "dev"]
                       :compiler     dev-config}]})

;;; Tasks --------------------------------------------------------------------------------

(defmulti task first)

(defmethod task :default [_]
  (task ["repl"]))

(defmethod task "compile" [_]
  (api/build source-dir compiler-config))

(defmethod task "repl" [_]
  (ensure-nrepl-port!)
  (figwheel.nrepl/start-nrepl-server nrepl-options nil)
  (println "Started nREPL server on port:" (:nrepl-port nrepl-options)))

(defmethod task "figwheel" [_]
  (ensure-nrepl-port!)
  (figwheel/start-figwheel! figwheel-options)
  (figwheel/cljs-repl))

(task *command-line-args*)

deps.edn

{:paths ["src" "dev"]
 :deps
 {org.clojure/clojure       {:mvn/version "1.9.0"}

  ;; For Spec
  org.clojure/test.check    {:mvn/version "0.9.0"}

  ;; ClojureScript
  org.clojure/clojurescript {:mvn/version "1.9.946"}
  com.cemerick/piggieback   {:mvn/version "0.2.2" :exclusions
                             [com.google.javascript/closure-compiler]}
  figwheel-sidecar          {:mvn/version "0.5.14" :exclusions
                             [com.google.javascript/closure-compiler]}

  ;; REPL
  org.clojure/tools.nrepl   {:mvn/version "0.2.12"}
  cider/cider-nrepl         {:mvn/version "0.16.0"}
  refactor-nrepl            {:mvn/version "2.3.1"}}}

I used these as a start for a project template of sorts. https://github.com/PEZ/deps-edn-figwheel

I sort of merged the Figwheel starter project and this gist. Planning to create a tutorial for absolute beginners. If I get the time for it.