02_next.ts

/*
 * Copyright 2023 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 { connect } from "../../src/mod.ts";
import { setupStreamAndConsumer } from "./util.ts";

// create a connection
const nc = await connect();

// create a stream with a random name with some messages and a consumer
const { stream, consumer } = await setupStreamAndConsumer(nc);

// retrieve an existing consumer
const js = nc.jetstream();
const c = await js.consumers.get(stream, consumer);

// the consumer is simply asked for one message by default
// this will resolve in 30s or null is returned
const m = await c.next();
if (m) {
  console.log(m.subject);
  m.ack();
} else {
  console.log(`didn't get a message`);
}

await nc.close();