producer.js

const { Kafka } = require('@confluentinc/kafka-javascript').KafkaJS;

async function producerStart() {
    const producer = new Kafka().producer({
        'bootstrap.servers': 'localhost:9092',
        'acks': 'all',
    });

    await producer.connect();
    console.log("Connected successfully");

    const res = []
    for (let i = 0; i < 50; i++) {
        res.push(producer.send({
            topic: 'test-topic',
            messages: [
                {
                    value: 'v1',
                    partition: 0,
                    key: 'x',
                    headers: {
                        'header1': ['h1v1', 'h1v2'],
                        'header3': 'h3v3',
                    }
                },
                {
                    value: 'v2',
                    key: 'y',
                }
            ]
        }));
    }

    const produceRecords = await Promise.all(res);

    // Produce records is an array of delivery reports for each call to `send`.
    // In case `messages` contains more than one message to the same topic-partition, only the last
    // delivery report is included in the array.
    console.log("Produced messages, first delivery report:\n" + JSON.stringify(produceRecords[0], null, 2));
    console.log("Produced messages, last delivery report:\n" + JSON.stringify(produceRecords[produceRecords.length - 1], null, 2));

    await producer.disconnect();

    console.log("Disconnected successfully");
}

producerStart();