feat: add an option to not start a websocket server (#16219)

Author: sheremet-va

packages/vite/src/node/server/index.ts

@@ -101,6 +101,11 @@ export interface ServerOptions extends CommonServerOptions {
    * Configure HMR-specific options (port, host, path & protocol)
    */
   hmr?: HmrOptions | boolean
+  /**
+   * Do not start the websocket connection.
+   * @experimental
+   */
+  ws?: false
   /**
    * Warm-up files to transform and cache the results in advance. This improves the
    * initial page load during server starts and prevents transform waterfalls.

packages/vite/src/node/server/ws.ts

@@ -85,11 +85,31 @@ const wsServerEvents = [
   'message',
 ]
 
+function noop() {
+  // noop
+}
+
 export function createWebSocketServer(
   server: HttpServer | null,
   config: ResolvedConfig,
   httpsOptions?: HttpsServerOptions,
 ): WebSocketServer {
+  if (config.server.ws === false) {
+    return {
+      name: 'ws',
+      get clients() {
+        return new Set<WebSocketClient>()
+      },
+      async close() {
+        // noop
+      },
+      on: noop as any as WebSocketServer['on'],
+      off: noop as any as WebSocketServer['off'],
+      listen: noop,
+      send: noop,
+    }
+  }
+
   let wss: WebSocketServerRaw_
   let wsHttpServer: Server | undefined = undefined