fix: reconnected should also be fired before retrying the command (#482)

Author: uki00a

Diff for: connection.ts

@@ -360,15 +360,18 @@ export class RedisConnection
         return command.reject(error);
       }
 
+      let backoff = 0;
       for (let i = 0; i < this.maxRetryCount; i++) {
         // Try to reconnect to the server and retry the command
         this.#close(true);
         try {
+          this.#dispatchEvent("reconnecting", { delay: backoff });
           await this.connect();
           const reply = await command.execute();
           return command.resolve(reply);
-        } catch { // TODO: use `AggregateError`?
-          const backoff = this.backoff(i);
+        } catch (error) {
+          this.#dispatchEvent("error", { error }); // TODO: use `AggregateError`?
+          backoff = this.backoff(i);
           await delay(backoff);
         }
       }

Diff for: tests/reconnect_test.ts

@@ -1,4 +1,4 @@
-import { assertEquals } from "../deps/std/assert.ts";
+import { assertEquals, assertInstanceOf } from "../deps/std/assert.ts";
 import { beforeAll, describe, it } from "../deps/std/testing.ts";
 import { newClient, nextPort, startRedis, stopRedis } from "./test_util.ts";
 
@@ -13,10 +13,16 @@ describe("reconnect", () => {
     const client = await newClient({ hostname: "127.0.0.1", port });
     assertEquals(await client.ping(), "PONG");
     await stopRedis(server);
+    let reconnectingFired = 0;
+    client.addEventListener("reconnecting", (e) => {
+      reconnectingFired++;
+      assertInstanceOf(e, CustomEvent);
+    });
     server = await startRedis({ port });
     assertEquals(await client.ping(), "PONG");
     client.close();
     await stopRedis(server);
+    assertEquals(reconnectingFired, 1);
   });
 
   it("auto reconnect, with db spec", async () => {