async和await 如何使用？

async和await是ES7引入的新语法，可以更加方便的异步操作

async关键字用在函数上(async函数的返回值是promise实例对象)

await必须跟async同时使用。

例子：

// 获取数据1
    getDatas1() {
      return new Promise((resolve, reject) => {
        this.$http
          .get(window.SITE_CONFIG.apiURL + "/static/queryStatic", {
            params: {
              dictType: "accept_promotion",
            },
          })
          .then((res) => {
            let result = res.body.data;
 
            this.ycslArr1 = result;
            resolve("嘿嘿嘿1")
          })
        .catch(() => {});
      });
    },
    
// 获取数据2
    getDatas2() {
      return new Promise((resolve, reject) => {
        this.$http
          .post(window.SITE_CONFIG.apiURL + "/service656", {
            machineCode: "SfJjeyP0xmnS6h8R",
            url: "/power/getItemCountByOnlineDepth/1.0",
            postdata: {},
          })
          .then((res) => {
            let result = JSON.parse(res.body.result).data;
            this.wbsdData2.pop();
            resolve("嘿嘿嘿222");
          })
          .catch(() => {});
      });
    },
    
     async query() {
      let ret1 = await this.getDatas1();
      var ret2 = await this.getDatas2();
      console.log("ret1????", ret1, ret2); // 嘿嘿嘿1,嘿嘿嘿222
    },