fix(browser): produce valid config file if preview provider is used (#6305)

Author: sheremet-va

docs/package.json

@@ -15,7 +15,7 @@
   },
   "dependencies": {
     "@vueuse/core": "^10.11.0",
-    "vue": "^3.4.35"
+    "vue": "^3.4.37"
   },
   "devDependencies": {
     "@iconify-json/carbon": "^1.1.37",

packages/ui/package.json

@@ -82,7 +82,7 @@
     "unplugin-vue-components": "^0.27.3",
     "vite": "^5.0.0",
     "vite-plugin-pages": "^0.32.3",
-    "vue": "^3.4.35",
+    "vue": "^3.4.37",
     "vue-router": "^4.4.2",
     "vue-virtual-scroller": "2.0.0-beta.8"
   }

packages/vitest/src/create/browser/creator.ts

@@ -277,7 +277,7 @@ async function generateWorkspaceFile(options: {
     `  },`,
     `])`,
     '',
-  ].filter(c => c != null).join('\n')
+  ].filter(c => typeof c === 'string').join('\n')
   await writeFile(options.configPath, workspaceContent)
 }
 
@@ -308,7 +308,7 @@ async function generateFrameworkConfigFile(options: {
     `  },`,
     `})`,
     '',
-  ].join('\n')
+  ].filter(t => typeof t === 'string').join('\n')
   // this file is only generated if there is already NO root config which is an edge case
   await writeFile(options.configPath, configContent)
 }