Kill process if www/js/player.js is not found at startup

index.js

@@ -10,6 +10,8 @@ if (parseInt(ver[1], 10) < 6) {
     process.exit(1);
 }
 
+checkPlayerExists();
+
 const args = parseArgs();
 
 if (args.has('--daemonize')) {
@@ -77,3 +79,20 @@ function parseArgs() {
 
     return args;
 }
+
+function checkPlayerExists() {
+    const fs = require('fs');
+    const path = require('path');
+
+    const playerDotJs = path.join(__dirname, 'www', 'js', 'player.js');
+
+    if (!fs.existsSync(playerDotJs)) {
+        console.error(
+            'Missing video player: www/js/player.js.  This should have been ' +
+            'automatically generated by the postinstall step of ' +
+            '`npm install`, but you can manually regenerate it by running ' +
+            '`npm run build-player`'
+        );
+        process.exit(1);
+    }
+}

package.json

@@ -2,7 +2,7 @@
   "author": "Calvin Montgomery",
   "name": "CyTube",
   "description": "Online media synchronizer and chat",
-  "version": "3.55.5",
+  "version": "3.55.6",
   "repository": {
     "url": "http://github.com/calzoneman/sync"
   },