typescript 在预期流的地方提供了“未定义”
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Provided 'undefined' where stream was expected
提问by curious95
I am trying to send chained http requests using Rxjs, but I am getting this error...
我正在尝试使用 Rxjs 发送链接的 http 请求，但出现此错误...
Error: Uncaught (in promise): TypeError: You provided 'undefined' where a stream was expected. You can provide an Observable, Promise, Array, or Iterable. TypeError: You provided 'undefined' where a stream was expected. You can provide an Observable, Promise, Array, or Iterable.
错误：未捕获（承诺）：类型错误：您在需要流的地方提供了“未定义”。您可以提供 Observable、Promise、Array 或 Iterable。类型错误：您在需要流的地方提供了“未定义”。您可以提供 Observable、Promise、Array 或 Iterable。
I want to get location object from my API, then I want to get latitude and longitude based on location.address.
我想从我的 API 中获取位置对象，然后我想基于location.address.
declare const require : any;
@Injectable()
export class GoogleMapLocationResolver implements Resolve<{location: Location, longitude: number, latitude: number }> {
constructor( private locationService: LocationService,
private route: ActivatedRoute,
private router: Router){}
resolve(route: ActivatedRouteSnapshot, state: RouterStateSnapshot): {location: Location, longitude: number, latitude: number } | Observable<{location: Location, longitude:number, latitude: number }> | Promise<{location: Location, longitude: number, latitude: number }> {
let geocoder = require('geocoder');
return this.locationService.getLocation(route.params['id']).map(
(response: Response)=> { return response.json() }
).mergeMap(location => geocoder.geocode(location.address, function(err, data){
let latitude
let longitude
if(data.status === 'OK'){
console.log('Status ok: ')
console.log(data)
let results = data.results;
latitude = results[0].geometry.location.lat;
longitude = results[0].geometry.location.lng;
console.log(latitude); // PRINTS CORRECT
console.log(longitude); // PRINTS CORRECT
}
return {location, longitude, latitude};
})).catch(error => {
this.router.navigate(['/not-found'])
return Observable.throw(error);
})
}
}
NOTE:Whats very weird is that after this error, console prints latitude and longitude correct! ('// PRINTS CORRECT' comment)
注意：非常奇怪的是，在此错误之后，控制台打印正确的纬度和经度！（'// 打印正确' 注释）
EDIT: Yep my mistake, I declared variables in if, but that was not a problem at the end. Posting solution soon.
编辑：是的，我的错误，我在 if 中声明了变量，但这最终不是问题。很快发布解决方案。
回答by curious95
I solved it... Problem is that geocoder.geocode()function has no return value, while mergeMap()is expecting an Promise,Observableetc, geocoder.geocode()returned undefined. My solution is to wrap this function with Promise.
我解决它......问题是，geocoder.geocode()函数没有返回值，而mergeMap()期待的Promise，Observable等geocoder.geocode()返回undefined。我的解决方案是用Promise.
declare const require : any;
@Injectable()
export class GoogleMapLocationResolver implements Resolve<{location: Location, longitude: number, latitude: number }> {
constructor( private locationService: LocationService,
private route: ActivatedRoute,
private router: Router){}
resolve(route: ActivatedRouteSnapshot, state: RouterStateSnapshot): {location: Location, longitude: number, latitude: number } | Observable<{location: Location, longitude:number, latitude: number }> | Promise<{location: Location, longitude: number, latitude: number }> {
let geocoder = require('geocoder');
return this.locationService.getLocation(route.params['id']).map(
(response: Response)=> { return response.json() }
).mergeMap( location => new Promise<any>((resolve, reject) => {geocoder.geocode(location.address, function(err, data){
let latitude
let longitude
if(data.status === 'OK'){
console.log('Status ok: ')
console.log(data)
let results = data.results;
latitude = results[0].geometry.location.lat;
longitude = results[0].geometry.location.lng;
console.log(latitude);
console.log(longitude);
}
resolve({location, longitude, latitude}(;
})
})).catch(error => {
this.router.navigate(['/not-found'])
return Observable.throw(error);
})
}
