等所有接口异步调用完成后再执行如何实现 使用async await

需求：initChart()初始化图表方法要在前面四个异步调用全部完成获取到数据后再执行~
话不多说，直接上代码：

 created() {
 	this.fetchAllInterface();
 },
 methods: {
     async fetchAllInterface() {
         await this.getUserTotal();
         await this.getBookTotal();
         await this.getSeatItemTotal();
         await this.getRentalTotal();
         this.initChart();
     },
     initChart() {
         let myChart = echarts.init(document.getElementById('main'));
         // 绘制图表
         myChart.setOption({
             title: {
                 text: '统计'
             },
             tooltip: {
                 trigger: 'axis'
             },
             grid: {
                 left: '3%',
                 right: '4%',
                 bottom: '3%',
                 containLabel: true
             },
             xAxis: {
                 type: 'category',
                 data: ['今日借阅数', '今日预约数', '图书数', '用户数'],
                 axisTick: {
                     alignWithLabel: true
                 }
             },
             yAxis: {
                 type: 'value'
             },
             series: [
                 {
                     type: 'bar',
                     barWidth: '25%',
                     data: [
                         {
                             value: this.rentalTotal,
                             itemStyle: { color: '#5470c6' }
                         },
                         {
                             value: this.seatItemTotal,
                             itemStyle: { color: '#91cc75' }
                         },
                         {
                             value: this.bookTotal,
                             itemStyle: { color: '#fac858' }
                         },
                         {
                             value: this.userTotal,
                             itemStyle: { color: '#ee6666' }
                         }
                     ]
                 }
             ]
         })
     },
     getUserTotal() {
         return this.$ajax.post("/user/total").then((response)=>{
             let resp = response.data;
             if(resp.code === 0){
                 this.userTotal = resp.data;
             }
         });
     },
     getBookTotal() {
         return this.$ajax.post("/book/total").then((response)=>{
             let resp = response.data;
             if(resp.code === 0){
                 this.bookTotal = resp.data;
             }
         });
     },
     getSeatItemTotal() {
         return this.$ajax.post("/seat/dayTotal").then((response)=>{
             let resp = response.data;
             if(resp.code === 0){
                 this.seatItemTotal = resp.data;
             }
         });
     },
     getRentalTotal() {
         return this.$ajax.post("/book/dayTotal").then((response)=>{
             let resp = response.data;
             if(resp.code === 0){
                 this.rentalTotal = resp.data;
             }
         });
     }
 }

注意点： axios异步调用记得return返回，要不然await不生效。