Question

我正在尝试使用Rxjs发送链式http请求，但我收到此错误...

错误：未捕获（在承诺中）：TypeError：您提供了未定义的＆＃39;预期流的地方。您可以提供Observable，Promise，Array或Iterable。 TypeError：您提供了＆＃39; undefined＆＃39;预期流的地方。您可以提供Observable，Promise，Array或Iterable。

我想从我的API获取位置对象，然后我希望根据location.address得到纬度和经度。

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);
    })  
  }
}

注意：非常奇怪的是，在此错误之后，控制台打印纬度和经度正确！（＆＃39; // PRINTS CORRECT＆＃39;评论）

编辑：是的，我错了，我在if中声明了变量，但最后这不是问题。很快发布解决方案。

Answer 1

我解决了......问题是geocoder.geocode()函数没有返回值，而mergeMap()期待Promise，Observable等，geocoder.geocode()返回undefined。我的解决方案是使用Promise包装此函数。

    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);
            })  
          }

提供＆＃39; undefined＆＃39;预计流量在哪里

1 个答案: