this is how it was introduced

  methods: {
    loadMap() {
      return new Promise(function(resolve, reject) {
        window.init = function() {
          resolve(qq);
        };
        var script = document.createElement("script");
        script.type = "text/javascript";
        script.src = "https://map.qq.com/api/js?v=2.exp&callback=init";
        script.onerror = reject;
        document.head.appendChild(script);
      });
    },
    init() {
      var mapLatlng = new qq.maps.LatLng(39.916527, 116.397128);
      var mapOptions = {
        center: mapLatlng,
        zoom: 9
      };
      var mapId = document.getElementById(this.idName);
      var mapQQ = new qq.maps.Map(mapId, mapOptions);
    }
  },

created() {
    var self = this;
    this.loadMap().then(function() {
      self.init();
    });
  }

there is no problem in introducing this into use, but it will prompt "qq" is not defined when packaging, there is a solution like this on the
website, but vue cli 3.0 only has vue.config.js file configuration. Not really.