error TS2322: Type 'Observable<any>' is not assignable to type 'string

update_user(user_to_update:any): Observable<any> {
        let json = JSON.stringify(user_to_update);
        let params = json;

        let headers = new HttpHeaders({ 'Content-Type': 'application/json',
                                        'Authorization': this.getToken() 
                                    });

        return this._http.put(this.url   'update-user/'   user_to_update._id, params, { headers: headers });

    }

Me sale este error en el 'Authorization':

error TS2322: Type 'Observable' is not assignable to type 'string | string[]'. Type 'Observable' is missing the following properties from type 'string[]': length, pop, push, concat, and 27 more.

47 'Authorization': this.getToken()

CodePudding user response：

I imagine this.getToken return an Observable, and "Authorization" should be an string

Your function update_user return an observable, but this observable need the result of another one. So you should use switchMap rjxs operator.

It's not very complex. The idea is

return observable_one.pipe(
       switchMap(res=>{
          //in res you has the response
          return observable_two
       }))

In your case

update_user(user_to_update:any): Observable<any> {
    let json = JSON.stringify(user_to_update);
    let params = json;

    return this.getToken().pipe(
      switchMap((authorization:any)=>{
          let headers = new HttpHeaders({ 'Content-Type': 'application/json',
                                    'Authorization': authorization 
                                });

            return this._http.put(this.url   'update-user/'   user_to_update._id, 
                   params, { headers: headers });
      })
    )
}

NOTE: Really you needn't use JSON.stringify, Angular make it for you so really your function becomes like

update_user(user_to_update:any): Observable<any> {

    return this.getToken().pipe(
      switchMap((authorization:any)=>{
          let headers = new HttpHeaders({ 'Content-Type': 'application/json',
                                    'Authorization': authorization 
                                });

            return this._http.put(this.url   'update-user/'   user_to_update._id, 
                   user_to_update, { headers: headers });
      })
    )
}