Add a single script to build and prepare demos locally (#31452)

Author: alexslavr

apps/demos/project.json

@@ -102,6 +102,25 @@
         "{projectRoot}/**/*"
       ],
       "cache": true
+    },
+    "prepare-js": {
+      "executor": "nx:run-script",
+      "options": {
+        "script": "prepare-js"
+      },
+      "dependsOn": [
+        { "projects": ["devextreme"], "target": "build" },
+        { "projects": ["devextreme-angular", "devextreme-react", "devextreme-vue"], "target": "pack" }
+      ],
+      "inputs": [
+        "default",
+        "{projectRoot}/gulpfile.js/**/*",
+        "{projectRoot}/rollup.devextreme-angular.umd.config.mjs"
+      ],
+      "outputs": [
+        "{projectRoot}/Demos/**/config.js"
+      ],
+      "cache": true
     }
   },
   "namedInputs": {

package.json

@@ -20,7 +20,8 @@
     "all:build": "ts-node tools/scripts/build-all.ts",
     "all:build-dev": "pnpm run all:build --dev",
     "all:pack-and-copy": "nx run-many -t pack-and-copy",
-    "webserver": "http-server --port 8080 -c-1"
+    "demos:prepare": "nx run devextreme-demos:prepare-js",
+    "demos:start": "http-server ./apps/demos --port 8080 -c-1"
   },
   "nx": {},
   "private": true,