nats.js/core/examples/snippets/sub_timeout.ts

/*
 * Copyright 2020-2021 The NATS Authors
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

// import the connect function from a transport
import { connect, errors } from "@nats-io/transport-deno";

// to create a connection to a nats-server:
const nc = await connect({ servers: "demo.nats.io:4222" });

// create subscription with a timeout, if no message arrives
// within the timeout, the subscription throws a timeout error
const sub = nc.subscribe("hello", { timeout: 1000 });
(async () => {
  for await (const _m of sub) {
    // handle the messages
  }
})().catch((err) => {
  if (err instanceof errors.TimeoutError) {
    console.log(`sub timed out!`);
  } else {
    console.log(`sub iterator got an error!`);
  }
  nc.close();
});

await nc.closed();