IoT Platform:Access IoT Platform by using MQTT over WebSocket connections

const iot = require('alibabacloud-iot-device-sdk');

// Specify the device certificate information. 
const productKey = 'a1W***';
const deviceName = 'device2';
const deviceSecret = 'ff01e59d1a***';

// Specify the instance ID of a public instance of the new version or an Enterprise Edition instance. If you use a public instance of the old version, you do not need to specify the instance ID. 
const instanceId = '';

// Specify the ID of the region to which the product and device belong. 
const region = 'cn-shanghai';

const brokerUrl = instanceId
  ? `wss://${instanceId}.mqtt.iothub.aliyuncs.com:443`
  : `wss://${productKey}.iot-as-mqtt.${region}.aliyuncs.com:443`;

const device = iot.device({
  productKey: `${productKey}`,
  deviceName: `${deviceName}`,
  deviceSecret: `${deviceSecret}`,
  brokerUrl,
  tls: true,
});

// Listen to connect events: Connect the device to IoT Platform over an MQTT connection, enable the device to subscribe to a custom topic, and use the custom topic to send messages to IoT Platform. 
device.on('connect', () => {
  device.subscribe(`/${productKey}/${deviceName}/user/get`);
  console.log('connect successfully!');
  device.publish(`/${productKey}/${deviceName}/user/update`, 'hello world!');
});

// Listen to message events. 
device.on('message', (topic, payload) => {
  console.log(topic, payload.toString());
});

// Listen to error events. 
device.on('error', (error) => {
  console.error(error);
});

// To disconnect the device from IoT Platform, delete the double slashes (//) at the beginning of the following code and call the end function. 
//device.end();

You must configure the parameters that are described in the following table based on the actual use case such as the device information.