refactor: add recovered flag after a successful recovery

Following b4e20c5

lib/socket.ts

@@ -167,7 +167,11 @@ export class Socket<
    * });
    */
   public connected: boolean = false;
-
+  /**
+   * Whether the connection state was recovered after a temporary disconnection. In that case, any missed packets will
+   * be transmitted by the server.
+   */
+  public recovered: boolean = false;
   /**
    * Credentials that are sent when accessing a namespace.
    *
@@ -651,6 +655,7 @@ export class Socket<
   private onconnect(id: string, pid: string) {
     debug("socket connected with id %s", id);
     this.id = id;
+    this.recovered = pid && this._pid === pid;
     this._pid = pid; // defined only if connection state recovery is enabled
     this.connected = true;
     this.emitBuffered();

test/connection-state-recovery.ts

@@ -9,7 +9,9 @@ describe("connection state recovery", () => {
         forceNew: true,
       });
 
-      socket.emit("hi");
+      expect(socket.recovered).to.eql(false);
+
+      socket.emit("hi"); // init the offset
 
       socket.on("hi", () => {
         const id = socket.id;
@@ -18,6 +20,7 @@ describe("connection state recovery", () => {
 
         socket.on("connect", () => {
           expect(socket.id).to.eql(id); // means that the reconnection was successful
+          expect(socket.recovered).to.eql(true); // means that the reconnection was successful
           done();
         });
       });