don't start dev server until bundle is generated (sveltejs#73)

* don't start dev server until bundle is generated (sveltejs#72)

* extract `npm run start:dev` spawn into separate file

Author: Conduitry

package.json

@@ -2,7 +2,6 @@
   "name": "svelte-app",
   "version": "1.0.0",
   "devDependencies": {
-    "npm-run-all": "^4.1.5",
     "rollup": "^1.12.0",
     "rollup-plugin-commonjs": "^10.0.0",
     "rollup-plugin-livereload": "^1.0.0",
@@ -16,8 +15,7 @@
   },
   "scripts": {
     "build": "rollup -c",
-    "autobuild": "rollup -c -w",
-    "dev": "run-p start:dev autobuild",
+    "dev": "rollup -c -w",
     "start": "sirv public --single",
     "start:dev": "sirv public --single --dev"
   }

rollup.config.js

@@ -3,6 +3,7 @@ import resolve from 'rollup-plugin-node-resolve';
 import commonjs from 'rollup-plugin-commonjs';
 import livereload from 'rollup-plugin-livereload';
 import { terser } from 'rollup-plugin-terser';
+import rollup_start_dev from './rollup_start_dev';
 
 const production = !process.env.ROLLUP_WATCH;
 
@@ -36,6 +37,10 @@ export default {
 		}),
 		commonjs(),
 
+		// In dev mode, call `npm run start:dev` once
+		// the bundle has been generated
+		!production && rollup_start_dev,
+
 		// Watch the `public` directory and refresh the
 		// browser on changes when not in production
 		!production && livereload('public'),

rollup_start_dev.js

@@ -0,0 +1,12 @@
+import * as child_process from 'child_process';
+
+let running_dev_server = false;
+
+export default {
+	writeBundle() {
+		if (!running_dev_server) {
+			running_dev_server = true;
+			child_process.spawn('npm', ['run', 'start:dev'], { stdio: ['ignore', 'inherit', 'inherit'] });
+		}
+	}
+};