通俗易懂直接上代码：
先了解下promise

let p1 = new Promise((resolve, reject) => {
  resolve('成功了')
})
 
let p2 = new Promise((resolve, reject) => {
  resolve('success')
})
 
let p3 = Promse.reject('失败')
 
Promise.all([p1, p2]).then((result) => {
  console.log(result)               //['成功了', 'success']
}).catch((error) => {
  console.log(error)
})
 
Promise.all([p1,p3,p2]).then((result) => {
  console.log(result)
}).catch((error) => {
  console.log(error)      // 失败了，打出 '失败'
})

实际中调用代码使用：

getDate(){
      let p1 = new Promise(resolve => {
           request.projectChartCalculationWork().then(({ r }) => {  //调用后台接口
                    resolve(r)
                })
           })
      let p2 = new Promise(resolve => {
            request.formInterfacesPrdOperatingNum_kl({}).then(({ r }) => {
                    resolve(r)
                })
            })
       Promise.all([p1, p2]).then(res => {
            console.log(res[0])  // P1结果
            console.log(res[1])  // P2结果    
        })

}

注意：错误返回reject需要自己加上