Question

我想在其他3个数组的帮助下构造一个数组。我为此目的使用JS承诺但是无法正确实现。所以我基本上想要做的是先填充一个数组。

let getPlacePromise = function() {
      return new Promise(function(resolve,reject){
        this.getplaceArray= this.getfilterPlaces(inputdata);
        resolve("got places\n" ); 
      });
  };

  let getTransporterPromise= function(message) {
    return new Promise(function(resolve,reject){
      this.getTransporterArray= this.getfilterTransporter(inputdata);
      resolve(message+"got Transporter"); 
    });
  }; 

  let getVehiclePromise = function(message) {
    return new Promise(function(resolve,reject){
      this.getVehicleArray= this.getfilterVehicles(inputdata);
      resolve(message+"got vehicle"); 
    });
  };

  getPlacePromise().then(function(result){
      return getTransporterPromise(result);
  }).then(function(result){
      return getVehiclePromise(result);
  }).then(function(result){
    this.AllDropdownValues= this.getTransporterArray.concat(this.getVehicleArray);
  });

我知道这段代码应该有错误。我无法提出正确的实施方案。我希望 getplaceArray 首先填充，而不是仅应完成其他其他数组。是否可以在promises中调用函数。我在这里遇到的错误是 getplaceArray，getTransporterArray，getVehicleArray 未定义。

getfilterTransporter函数：

getfilterTransporter(autocompleteInputData) {

var k= this.checkRegex(autocompleteInputData);
this.getfilteredTransporter= this.filterTransporters(k);
return this.formatTransporterValue(this.getfilteredTransporter);

}

getfilterVehicle：

getfilterVehicles(autocompleteInputData) {

  var k= this.checkRegex(autocompleteInputData);
    this.getfilteredVehicle= this.filterVehicles(k);
    return this.formatVehicleValue(this.getfilteredVehicle);
}

getfilterPlace

getfilterPlaces(autocompleteInputData) {
  if (autocompleteInputData == '' || typeof(autocompleteInputData) == 'object') 
  return null;
  this.placeData.getPlacesFromPig(autocompleteInputData)
  .subscribe(response => {
     return this.formatPigResponse(response);
   }); 

}

修改：

稍微修改了答案。休息正在运行但是 this.getfilterPlaces ，其中有一个在其中运行的订阅方法来填充数据不起作用。

let a=[], b=[],c=[];
    a=  this.getfilterPlaces(inputdata);
    b= this.getfilterTransporter(inputdata);
    c= this.getfilterVehicles(inputdata);

    let getplaceArray = [],
  getTransporterArray = [],
  getVehicleArray = [];

let getPlacePromise = function () {
  const self = this;
  return new Promise(function (resolve, reject) {
    getplaceArray = a;
    resolve("got places\n");
  });
};

let getTransporterPromise = function (message) {
  const self = this;
  return new Promise(function (resolve, reject) {
    getTransporterArray =  b
    resolve(message + "got Transporter");
  });
};

let getVehiclePromise = function (message) {
  const self = this;
  return new Promise(function (resolve, reject) {
    getVehicleArray = c
    resolve(message + "got vehicle");
  });
};

getPlacePromise().then(function (result) {
  return getTransporterPromise(result);
}).then(function (result) {
  return getVehiclePromise(result);
}).then(function (result) {
  var AllDropdownValues = getTransporterArray.concat(getVehicleArray).concat(getplaceArray);
  console.log(AllDropdownValues);
});

答案是 使用async和await.Below是代码。

async function getfilterPlaces(autocompleteInputData) {
  if (autocompleteInputData == '' || typeof(autocompleteInputData) == 'object') 
    return null;
  return this.placeData.getPlacesFromPig(autocompleteInputData)
    .toPromise()
    .then(response => this.formatPigResponse(response));
}

调用函数filterAllComponent（inputdata）时

：

async function filterAllComponent(inputdata) {
  let a=[], b=[], c=[];
  a = await this.getfilterPlaces(inputdata);
  b = this.getfilterTransporter(inputdata);
  c = this.getfilterVehicles(inputdata);
[...]

Answer 1

试试这个

let getplaceArray = [],
  getTransporterArray = [],
  getVehicleArray = [];

let getPlacePromise = function () {
  const self = this;
  return new Promise(function (resolve, reject) {
    getplaceArray = self.getfilterPlaces(inputdata);
    resolve("got places\n");
  });
};

let getTransporterPromise = function (message) {
  const self = this;
  return new Promise(function (resolve, reject) {
    getTransporterArray = self.getfilterTransporter(inputdata);
    resolve(message + "got Transporter");
  });
};

let getVehiclePromise = function (message) {
  const self = this;
  return new Promise(function (resolve, reject) {
    getVehicleArray = self.getfilterVehicles(inputdata);
    resolve(message + "got vehicle");
  });
};

getPlacePromise().then(function (result) {
  return getTransporterPromise(result);
}).then(function (result) {
  return getVehiclePromise(result);
}).then(function (result) {
  this.AllDropdownValues = getTransporterArray.concat(getVehicleArray);
});

Promise用于从不同数组中连接数组

1 个答案: