diff --git a/npm/vite-dev-server/src/index.ts b/npm/vite-dev-server/src/index.ts
index f5197353b5f7..0e063347bdb2 100644
--- a/npm/vite-dev-server/src/index.ts
+++ b/npm/vite-dev-server/src/index.ts
@@ -15,9 +15,9 @@ export async function startDevServer (startDevServerArgs: StartDevServerOptions)
   const viteDevServer = await createDevServer(startDevServerArgs)
 
   const app = await viteDevServer.listen()
-  const port = app.config.server.port
+  const port = app.config.server.port!
 
   debug('Component testing vite server started on port', port)
 
-  return { port, close: app.httpServer.close }
+  return { port, close: app.httpServer!.close }
 }
diff --git a/npm/vite-dev-server/src/makeCypressPlugin.ts b/npm/vite-dev-server/src/makeCypressPlugin.ts
index fc177ccbc912..5b908253cabd 100644
--- a/npm/vite-dev-server/src/makeCypressPlugin.ts
+++ b/npm/vite-dev-server/src/makeCypressPlugin.ts
@@ -106,7 +106,7 @@ export const makeCypressPlugin = (
         // as soon as we find one of the specs, we trigger the re-run of tests
         for (const mod of moduleImporters.values()) {
           debug('handleHotUpdate - mod.file', mod.file)
-          if (specsPathsSet.has(mod.file)) {
+          if (mod.file && specsPathsSet.has(mod.file)) {
             debug('handleHotUpdate - compile success')
             devServerEvents.emit('dev-server:compile:success', { specFile: mod.file })
 
diff --git a/npm/vite-dev-server/src/startServer.ts b/npm/vite-dev-server/src/startServer.ts
index ab2468b8e854..c2b1758de31e 100644
--- a/npm/vite-dev-server/src/startServer.ts
+++ b/npm/vite-dev-server/src/startServer.ts
@@ -37,7 +37,7 @@ const resolveServerConfig = async ({ viteConfig, options }: StartDevServerOption
 
   const finalConfig: InlineConfig = { ...viteConfig, ...requiredOptions }
 
-  finalConfig.plugins = [...(viteConfig.plugins || []), makeCypressPlugin(projectRoot, supportFile, options.devServerEvents, options.specs)]
+  finalConfig.plugins = [...(finalConfig.plugins || []), makeCypressPlugin(projectRoot, supportFile, options.devServerEvents, options.specs)]
 
   // This alias is necessary to avoid a "prefixIdentifiers" issue from slots mounting
   // only cjs compiler-core accepts using prefixIdentifiers in slots which vue test utils use.
diff --git a/npm/vite-dev-server/tsconfig.json b/npm/vite-dev-server/tsconfig.json
index f63cf8e16f78..e194d3002e04 100644
--- a/npm/vite-dev-server/tsconfig.json
+++ b/npm/vite-dev-server/tsconfig.json
@@ -24,7 +24,7 @@
     // "isolatedModules": true,               /* Transpile each file as a separate module (similar to 'ts.transpileModule'). */
 
     /* Strict Type-Checking Options */
-    "strict": false /* Enable all strict type-checking options. */,
+    "strict": true,                           /* Enable all strict type-checking options. */
     "noImplicitAny": false,
 
     /* Module Resolution Options */