var options = {
  'username': username,
  'password': password,
  'clientId': clientId,
  'keepalive': 90,
  'connectTimeout': 3000
}
var client = mqtt.connect('wxs://xxxxx',options)
var topic = ‘xxx’
client.on('connect', function() {
  client.subscribe(topic, { 'qos': 0 })
  console.log('链接上')
})

client.on('message', function(topic, message) {
  console.log('topic:' + topic + ' msg:' + message.toString())
})

var i = 0
setInterval(function() {
  client.publish(topic, 'Hello mqtt ' + (i++))

}, 1000)

报错

mqtt版本"^4.3.7"， 哪位大神看下哪里错了呢？