Merge pull request 'Hot reload for Elm application' (#6) from nix-frontend-hot-reload into main

Reviewed-on: #6

Makefile

@@ -40,12 +40,9 @@ backend:
 
 serve: frontend backend
 ifeq ($(DEBUG),1)
-	RUST_LOG=info,actix_web=debug $(CARGO_RUN) --manifest-path=$(BACKEND_DIR)/Cargo.toml
+	$(MAKE) -C $(FRONTEND_DIR) serve DEBUG=1 & \
+	RUST_LOG=info,actix_web=debug $(CARGO_RUN) --manifest-path=$(BACKEND_DIR)/Cargo.toml; \
+	kill %1
 else ifeq ($(RELEASE),1)
 	$(CARGO_RUN) --release --manifest-path=$(BACKEND_DIR)/Cargo.toml
 endif
-
-clean:
-	rm -rf $(PUBLIC_DIR)/*
-	rm -rf $(BACKEND_DIR)/target
-	make -C $(FRONTEND_DIR) clean

README.md

@@ -12,6 +12,13 @@ make serve RELEASE=1 # can also do DEBUG=1 instead
 
 Now open `http://127.0.0.1:8080` in your browser.
 
+# Elm application hot reloading
+
+Hot reloading for Elm application is exposed at port `8000` under `DEBUG=1` mode.
+
+`make serve DEBUG=1`
+visit `localhost:8000`
+
 # TODO
 
- - [ ] Address compiler warnings.
+ - [ ] Address compiler warnings.

flake.nix

@@ -99,6 +99,29 @@
                   }
                 )
               ) { };
+
+              elm-go = prev.callPackage (
+                {
+                  lib,
+                  buildNpmPackage,
+                  elmPackages,
+                }:
+                buildNpmPackage {
+                  name = "elm-go";
+                  version = "5.0.20";
+                  src = pkgs.fetchFromGitHub {
+                    owner = "lucamug";
+                    repo = "elm-go";
+                    rev = "9a7bd8c980a03b026128fcd626b9395b4e2cb1e0";
+                    sha256 = "sha256-B5Cngv8EGOY79u9aZeixA3EBt8rIc6bkYA4zoqycpk8=";
+                  };
+                  npmDepsHash = "sha256-0LfLpUbav8cVoZ9/Cjb7Mr8jdo1/KjVcjR4lcYB3AzY=";
+                  dontNpmBuild = true;
+                  makeWrapperArgs = [
+                    "--suffix PATH : ${lib.makeBinPath [ elmPackages.elm ]}"
+                  ];
+                }
+              ) { };
             })
           ];
         };
@@ -113,6 +136,9 @@
           with pkgs;
           mkShell {
             inputsFrom = [ example-spa-elm-app ];
+            buildInputs = [
+              elm-go
+            ];
           };
       }
     );

frontend/Makefile

@@ -2,7 +2,7 @@ SRC_FILES := $(shell find src -name "*.elm")
 
 all: elm.min.js
 
-.PHONY: elm.min.js
+.PHONY: elm.min.js serve
 
 ifeq ($(DEBUG)$(RELEASE),) # Both are empty
 $(error You must set exactly one of DEBUG=1 or RELEASE=1)
@@ -12,7 +12,6 @@ ifeq ($(DEBUG)$(RELEASE),11) # Both are set
 $(error Both DEBUG and RELEASE cannot be set at the same time)
 endif
 
-
 elm.min.js:
 ifeq ($(DEBUG),1)
 	./build.sh --debug src/Main.elm
@@ -20,5 +19,12 @@ else ifeq ($(RELEASE),1)
 	./build.sh --optimize src/Main.elm
 endif
 
+serve:
+ifeq ($(DEBUG),1)
+	elm-go src/Main.elm --port=8000 --dir=../public --start-page=index.html -- --output=../public/elm.min.js
+else ifeq ($(RELEASE),1)
+	$(error Cannot use serve target with RELEASE=1)
+endif
+
 clean:
 	rm elm.js elm.min.js