angular - typescript 函数抛出错误以返回值

Question

这就是我想要完成的，我正在调用函数 getGeoLocationOfUser()，我应该返回用户的地理定位，函数应该仅在地理定位可用或出现错误时返回。

但上面的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。我们将不胜感激。

Answer 1

您需要在此处返回地理定位的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) 获取该值。

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