关于前端:async和await-如何使用

async和await是ES7引入的新语法，能够更加不便的异步操作

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同时应用。

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    },