fix(sio-client): close the engine upon decoding exception

packages/socket.io-client/lib/manager.ts

@@ -531,7 +531,6 @@ export class Manager<
     this.skipReconnect = true;
     this._reconnecting = false;
     this.onclose("forced close");
-    if (this.engine) this.engine.close();
   }
 
   /**
@@ -544,14 +543,19 @@ export class Manager<
   }
 
   /**
-   * Called upon engine close.
+   * Called when:
+   *
+   * - the low-level engine is closed
+   * - the parser encountered a badly formatted packet
+   * - all sockets are disconnected
    *
    * @private
    */
   private onclose(reason: string, description?: DisconnectDescription): void {
     debug("closed due to %s", reason);
 
     this.cleanup();
+    this.engine?.close();
     this.backoff.reset();
     this._readyState = "closed";
     this.emitReserved("close", reason, description);

packages/socket.io-client/test/connection.ts

@@ -4,6 +4,7 @@ import hasCORS from "has-cors";
 import { install } from "@sinonjs/fake-timers";
 import textBlobBuilder from "text-blob-builder";
 import { BASE_URL, wrap } from "./support/util";
+import { nextTick } from "engine.io-client";
 
 describe("connection", () => {
   it("should connect to localhost", () => {
@@ -894,4 +895,30 @@ describe("connection", () => {
       });
     });
   });
+
+  it("should close the engine upon decoding exception", () => {
+    return wrap((done) => {
+      const manager = new Manager(BASE_URL, {
+        autoConnect: true,
+        reconnectionDelay: 50,
+      });
+
+      let engine = manager.engine;
+
+      manager.on("open", () => {
+        nextTick(() => {
+          // @ts-expect-error emit() is private
+          manager.engine.emit("data", "bad");
+        });
+      });
+
+      manager.on("reconnect", () => {
+        expect(manager.engine === engine).to.be(false);
+        expect(engine.readyState).to.eql("closed");
+
+        manager._close();
+        done();
+      });
+    });
+  });
 });