顺序承诺

Question

我知道这个问题已经研究了上千次，但是我尝试了很多解决方案，但仍然没有用。

我想链接来自http get的promise，但是我需要在运行下一个之前等待上一个，因为get方法返回给我一个数字，该数字被推送到数组中，并且需要正确排序。 / p>

我尝试过的方法：将每个promise放入数组中，然后使用reduce方法，但是没有用。 我认为棘手的事情是，我具有获取值发生变化的参数之一的条件。 这些值在一个数组中，所以我试图在等待时执行一次forEach，但是没有用。

这是我当前的代码：

async getAEObservable(checkIn: Date, checkOut: Date, adults: number, HotelID) {
    var In = checkIn;
    var Out =checkOut;


    var  promises=[];

    var id = []
    HotelID.forEach(element =>
      id.push(element))

    var index=0
    var ind = HotelID[0]
    if (HotelID.length !== 0) {
    if (ind !== "NULLNULL") {
      console.log('ok')
      const httpOptions = {
        headers: new HttpHeaders({
          'Content-Type': 'application/json',
          'Ama-Pos': '{"agentSine": "A9998WS","agentUserID": "AA","agentDutyCode": "GS","agencyDetails":{"currencyCode": "EUR","identifiers": [{"type": "IATA","id": "QIJI12151"}],"address":{"cityCode": "NCE","countryCode": "FR"}}}'
        })
      };

        let checkIn_param = this.transformDate(checkIn);
        let checkOut_param = this.transformDate(checkOut);
        let apiUrl = `${this.apiRoot_v0}?hotelIds=${ind.toString()}&checkInDate=${checkIn_param}&checkOutDate=${checkOut_param}&roomQuantity=1&adults=2&radius=5&radiusUnit=KM&rateCodes=RAC&paymentPolicy=NONE&includeClosed=true&bestRateOnly=true&view=FULL&sort=NONE`
        let url = `${apiUrl}`;
        console.log(url)
        return await this.apiCall(url, httpOptions, checkIn, checkOut, adults, HotelID); // here we are calling a function which contain a api call inside this function we are resolving the promise
      } else {

        // here we are not creating a promise bcs here we have simple push operation

        this.resAE.price.push(0)
        this.getAEObservable(checkIn, checkOut, adults, HotelID.slice(1));
        return this.resAE
      }
    }
    else {return this.resAE}
      }










async apiCall(url, httpOptions,checkIn, checkOut, adults, HotelID) {
   await new Promise(async (resolve, reject) => {
    await this.httpClient.get<any>(url, httpOptions).toPromise().then(result => {
      console.log(result)
      var price = result['data']['0']['offers']['0']['price']['total'];

      console.log(price)

      this.resAE.price.push(price);
      console.log(this.resAE)


  return this.resAE
    }).then(async resp => { if (HotelID.length !=0){
       this.getAEObservable(checkIn, checkOut, adults, HotelID.slice(1));}
      else{
      resolve();}
    }).catch(this.handleError)

  })

}






async apiCall(url, httpOptions,checkIn, checkOut, adults, HotelID) {
  return await new Promise(async (resolve, reject) => {
    this.httpClient.get<any>(url, httpOptions).toPromise().then(result => {
      console.log(result)
      var price = result['data']['0']['offers']['0']['price']['total'];

      console.log(price)

      this.resAE.price.push(price);
      console.log(this.resAE)

      return this.resAE;
    }).then(resp => { if (HotelID.length ===0){

      return this.resAE

    } else {
      this.getAEObservable(checkIn, checkOut, adults, HotelID.slice(1));
      resolve()};
    }).catch(this.handleError)
  })
}

想法是执行第一个get，填充我的数组，完成后，通过调用函数本身，但删除第一个getID的酒店ID，继续进行下一个get调用。

该数组已填充，因此没有其他问题，我认为这不是很好。

我只是编辑我的问题，说console.log（url）告诉我该URL是按良好顺序创建的

Answer 1

您可以尝试这样。

async getAEObservable(checkIn: Date, checkOut: Date, adults: number, HotelID) {
 console.log(HotelID);
    var In = checkIn;
    var Out =checkOut;

    var  promises=[];

    var id = []
    HotelID.forEach(element =>
    id.push(element))
    console.log(id)
    var index=0
    var ind = HotelID[0]
      if (ind !== "NULLNULL") {
        console.log('ok')
        const httpOptions = {
          headers: new HttpHeaders({
            'Content-Type': 'application/json',
            'Ama-Pos': '{"agentSine": "A9998WS","agentUserID": "AA","agentDutyCode": "GS","agencyDetails":{"currencyCode": "EUR","identifiers": [{"type": "IATA","id": "QIJI12151"}],"address":{"cityCode": "NCE","countryCode": "FR"}}}'
          })
        };

        let checkIn_param = this.transformDate(checkIn);
        let checkOut_param = this.transformDate(checkOut);
        let apiUrl = `${this.apiRoot_v0}?hotelIds=${ind.toString()}&checkInDate=${checkIn_param}&checkOutDate=${checkOut_param}&roomQuantity=1&adults=2&radius=5&radiusUnit=KM&rateCodes=RAC&paymentPolicy=NONE&includeClosed=true&bestRateOnly=true&view=FULL&sort=NONE`
        let url = `${apiUrl}`;
        console.log(url)
        return await apiCall(url, httpOptions); // here we are calling a function which contain a api call inside this function we are resolving the promise
      } else {

        // here we are not creating a promise bcs here we have simple push operation

        this.resAE.price.push(0)
        this.getAEObservable(checkIn, checkOut, adults, HotelID.slice(1));
        return this.resAE
      }

这是api调用函数

apiCall(url, httpOptions) {
 return new Promise((resolve, reject) => {
this.httpClient.get<any>(url, httpOptions).toPromise().then(res => {
            console.log(res)
            var price = res.data[0].offers[0].price.total;
            console.log(price)
            this.resAE.price.push( price);
            console.log(this.resAE)
            console.log(id)
            console.log(id.slice(1))
            return this.resAE;
          }).then( resp => {
             this.getAEObservable(checkIn, checkOut, adults, HotelID.slice(1))
             resolve();
         }).catch(this.handleError)
})
}