函数真的需要返回 promise 才能使 async-await 工作吗？

Question

我的疑问是，我可以编写一个普通函数并等待调用该函数吗？ 我会用一个例子更清楚地解释它 考虑这个函数

let splitStringAndConvertToInt=(data)=>{
  let splitData=data.split("-")
  let bothValues={
    first:parseInt(splitData[0]),
    last:parseInt(splitData[1])
  }
  return bothValues
 }

上面是我要调用的函数， 下面是主要功能

let allocateRoomAccordingToNeeds=async (request)=>{
  let mode=request.mode
  let totRooms=request.totalRooms
  let firstYearBtech=await splitStringAndConvertToInt(request.firstYearBtech)
  let secondYearBtech=await splitStringAndConvertToInt(request.secondYearBtech)
  let thirdYearBtech=await splitStringAndConvertToInt(request.thirdYearBtech)
  let fourthYearBtech=await splitStringAndConvertToInt(request.fourthYearBtech)
  let firstYearMtech=await splitStringAndConvertToInt(request.firstYearMtech)
  let secondYearMtech=await splitStringAndConvertToInt(request.secondYearMtech)
  let others=await splitStringAndConvertToInt(request.others)
  let tutors=await splitStringAndConvertToInt(request.tutors)
  let staff=await splitStringAndConvertToInt(request.staff)
  if (mode="Category" )
  {
   Room.updateMany({Room_number:{ $gte:firstYearBtech.first,$lte:firstYearBtech.last }}, {"$set":{"position": "1 year btech"}}, (err, writeResult) => {if(err){console.log("error in 1 btech"+err)} else{
     Room.updateMany({Room_number:{ $gte:secondYearBtech.first,$lte:secondYearBtech.last }}, {"$set":{"position": "2 year btech"}}, (err2, writeResult2) => {if(err2){console.log("error in 2 btech"+err2)} else{
       Room.updateMany({Room_number:{ $gte:thirdYearBtech.first,$lte:thirdYearBtech.last }}, {"$set":{"position": "3 year btech"}}, (err3, writeResult3) => {if(err3){console.log("error in 3 btech"+err3)} else{
         Room.updateMany({Room_number:{ $gte:fourthYearBtech.first,$lte:fourthYearBtech.last }}, {"$set":{"position": "4 year btech"}}, (err4, writeResult4) => {if(err4){console.log("error in 4 b tech"+err4)} else{
           Room.updateMany({Room_number:{ $gte:firstYearMtech.first,$lte:firstYearMtech.last }}, {"$set":{"position": "1 year mtech"}}, (err1m, writeResult1m) => {if(err1m){console.log("error in 1 mtech"+err1m)} else{
             Room.updateMany({Room_number:{ $gte:secondYearMtech.first,$lte:secondYearMtech.last }}, {"$set":{"position": "2 year mtech"}}, (err2m, writeResult2m) => {if(err2m){console.log("error in 2 mtech"+err2m)} else{
               Room.updateMany({Room_number:{ $gte:others.first,$lte:others.last }}, {"$set":{"position": "others"}}, (errO, writeResultO) =>{if(errO){console.log("error in others"+errO)} else{
                 Room.updateMany({Room_number:{ $gte:tutors.first,$lte:tutors.last }}, {"$set":{"position": "tutors"}}, (errT, writeResultT) => {if(errT){console.log("error in tutor"+errT)} else{
                   Room.updateMany({Room_number:{ $gte:staff.first,$lte:staff.last }}, {"$set":{"position": "staff"}}, (errS, writeResultS) => {
                      if(errS){
                         console.log("error in staff"+errS)
                      }
                      else{
                        console.log("Success allocation of Room")
                        res.send("Succes allocation of room")
                   }})
                 }})
               }})
             }})
           }})
         }})
       }})
     }})
   }});
  }
  else if(mode="Custom" ){
   Room.updateMany({"$set":{"position": "Custom"}}, (error, resultUp) => {
     if(error){
       console.log("error in Custom mode"+error)}
     else{
       console.log("successful upload of custom mode")
     }})
  }
}

以下是所有这些的根代码

   router.post('/authentication/changeallocationmode', function(req, res, next){
     //add code to assign same years to the given list if they are somewhere else and also add code to warn that given limit is not enough
       let vacate=req.body.vacate
       if(vacate==true){
         Room.updateMany({$set:{Roommates:["Null","Null","Null"],Occupied:false,Allocated:false}})
         .then(()=>{allocateRoomAccordingToNeeds(req.body)})
       }
       else {allocateRoomAccordingToNeeds(req.body)} /*this if-else is done to make it synchronous 
       so checking of vacate will be done and only after that other process will be done*/
     });

正如你在调用 splitToStringAndConvertToInt() 后看到的 有一个 Room.updateMany() 查询，因此需要在查询之前调用 await 以进行正确同步，因为 node.js 是异步的。 所以我需要知道的是，我可以这样调用 await 而不返回承诺吗？

Answer 1

是的，函数应该返回promise，或者函数本身使用async-await，那么你可以使用await，否则await就没有意义了

但你的函数不需要是 promise 或 async-await 因为它不需要时间来完成