打字稿函数抛出错误以返回值

Question

这是我想要完成的，我正在调用一个函数 getGeoLocationOfUser()，我应该返回用户的地理位置，并且函数应该仅在地理位置可用或出现错误时返回。

但上述函数抛出错误声明类型既不是“void”也不是“any”的函数必须返回一个值。

  public userGeolocation={latitude:null,longitude:null}

  getGeoLocationOfUser():{latitude:any,longitude:any}{
    this.geolocation.getCurrentPosition().then((resp) => {
    this.userGeolocation.latitude=resp.coords.latitude;
    this.userGeolocation.longitude=resp.coords.longitude;
    console.log(this.userGeolocation);

localStorage.setItem('userGeoLocation',JSON.stringify(this.userGeolocation));
return this.userGeolocation;
 //saving geolocation of user to localStorage

 }).catch((error) => {
  console.log('Error getting location', error);
  return this.userGeolocation;
});
}

我可能在这里遗漏了一个非常基本的概念。任何帮助将不胜感激。

Answer 1

您需要在此处返回地理位置的Promise。

//Make return type as Promise<object_type> or Promise<any>
 getGeoLocationOfUser():Promise<{latitude:any,longitude:any}>{
   //return the inner function
    return this.geolocation.getCurrentPosition().then((resp) => {
    this.userGeolocation.latitude=resp.coords.latitude;
    this.userGeolocation.longitude=resp.coords.longitude;
    console.log(this.userGeolocation);

localStorage.setItem('userGeoLocation',JSON.stringify(this.userGeolocation));
return this.userGeolocation;
 //saving geolocation of user to localStorage

 }).catch((error) => {
  console.log('Error getting location', error);
  return this.userGeolocation;
});
}

然后您可以通过调用function().then(callback) 来获取该值。

 getGeoLocationOfUser().then( loc =>{
     this.location = loc}).catch(err=>{});

Answer 2

请更改返回类型any 而不是{latitude:any,longitude:any}

getGeoLocationOfUser(): any {
      return  this.geolocation.getCurrentPosition().then((resp) => {
            this.userGeolocation.latitude = resp.coords.latitude;
            this.userGeolocation.longitude = resp.coords.longitude;
            console.log(this.userGeolocation);
            localStorage.setItem('userGeoLocation', JSON.stringify(this.userGeolocation));
            return this.userGeolocation;
            //saving geolocation of user to localStorage
        }).catch((error) => {
            console.log('Error getting location', error);
            return this.userGeolocation;
        });
} 

Answer 3

您可以尝试使用any 返回类型。

getGeoLocationOfUser(): Promise<any> {
    this.geolocation.getCurrentPosition().then((resp) => {
    this.userGeolocation.latitude=resp.coords.latitude;
    this.userGeolocation.longitude=resp.coords.longitude;
    console.log(this.userGeolocation);

    localStorage.setItem('userGeoLocation',JSON.stringify(this.userGeolocation));
    return this.userGeolocation;
    //saving geolocation of user to localStorage

 }).catch((error) => {
  console.log('Error getting location', error);
  return this.userGeolocation;
});
}