使用场景为需要请求4个接口，每个接口会返回一个数字，最终将他们相加显示出来。我使用下来，个人偏向于使用Async/Await，感觉代码更简洁、易读，就按顺序写下来就是了。

先是使用Promise的例子：

getTotalNum(){
    let getOneEvent = new Promise((resolve) => {
          this.$api.getApiOne(params).then(res => {
            if(res.status == 1){
              oneNum = res.body.num
            }
            resolve(oneNum)
          }).catch(function() {
        });
      })

    let getTwoEvent = new Promise((resolve) => {
          this.$api.getApiTwo(params).then(res => {
            if(res.status == 1){
              twoNum = res.body.num
            }
            resolve(twoNum)
          }).catch(function() {
        });
      })
    let getThreeEvent = new Promise((resolve) => {
          this.$api.getApiThree(params).then(res => {
            if(res.status == 1){
              threeNum = res.body.num
            }
            resolve(threeNum)
          }).catch(function() {
        });
      })
    let getFourEvent = new Promise((resolve) => {
          this.$api.getApiFour(params).then(res => {
            if(res.status == 1){
              fourNum = res.body.num
            }
            resolve(workflowNum)
          }).catch(function() {
        });
      })

    Promise.all([getOneEvent,getTwoEvent,getThreeEvent,getFourEvent]).then(() => {
          this.totalNum = oneNum + twoNum + threeNum + fourNum;
      }).catch((error) => {
          console.log(error)
      })
}

使用Async/Await：

async getTotalNum(){
    await this.$api.getApiOne(params).then(res => {
            if(res.status == 1){
              oneNum = res.body.num
            }
          }).catch(function() {
        });

    await this.$api.getApiTwo(params).then(res => {
            if(res.status == 1){
              twoNum = res.body.num
            }
          }).catch(function() {
        });
    await this.$api.getApiThree(params).then(res => {
            if(res.status == 1){
              threeNum = res.body.num
            }
          }).catch(function() {
        });
    await this.$api.getApiFour(params).then(res => {
            if(res.status == 1){
              fourNum = res.body.num
            }
          }).catch(function() {
        });
    this.totalNum = oneNum + twoNum + threeNum + fourNum;
}