npm i mqtt

<script src="https://unpkg.com/mqtt/dist/mqtt.min.js"></script>
<script>
    // 将在全局初始化一个 mqtt 变量
    console.log(mqtt)
</script>

npm i mqtt -g

mqtt help

MQTT.js command line interface, available commands are:

  * publish     publish a message to the broker
  * subscribe   subscribe for updates from the broker
  * version     the current MQTT.js version
  * help        help about commands

Launch 'mqtt help [command]' to know more about the commands.

// const mqtt = require('mqtt')
import mqtt from 'mqtt'

// 连接选项
const options = {
      clean: true, // true: 清除会话, false: 保留会话
      connectTimeout: 4000, // 超时时间
      // 认证信息
      clientId: '<your-client-id>',
      username: '<your-username>',
      password: '<your-password>',
}

// 连接字符串, 通过协议指定使用的连接方式
// ws 未加密 WebSocket 连接
// wss 加密 WebSocket 连接
// mqtt 未加密 TCP 连接
// mqtts 加密 TCP 连接
// wxs 微信小程序连接
// alis 支付宝小程序连接
const connectUrl = 'wss://mqtt-xxx.mqtt.tencenttdmq.com:8084/mqtt'
const client = mqtt.connect(connectUrl, options)

client.on('reconnect', (error) => {
    console.log('正在重连:', error)
})

client.on('error', (error) => {
    console.log('连接失败:', error)
})

client.on('message', (topic, message) => {
  console.log('收到消息：', topic, message.toString())
})