CODEWITHSUNDEEP
angularrxjsobservable
Ivar Reukers
Ivar Reukers

Reputation: 7719

Observable.map - Supplied parameter does not match any signature of call target

I have an angular 2 application. Upgraded from rxjs-5.0.0-beta.12 to rxjs-5.1.0 but now below this.http.get(...).map() shows an error.

Supplied parameters do not match any signature of call target

import { Http, Headers } from '@angular/http';
import { Observable } from 'rxjs/Observable';
import 'rxjs/add/operator/map';
import 'rxjs/add/operator/catch';

export class BaseService {
    private baseUrl: string = 'http://someserver:8080/somedb';

    constructor(public http: Http) {}

    doGet(url: string, headers?: Headers): Observable<any> {
        if(headers) {
            return this.http.get(this.baseUrl+url, {headers: headers}).map(response => {

            }, err => {

            });

        }
    }

}

Error only occurs when adding the .map(), did something change in the release?

Full IDE message:

[ts] Supplied parameters do not match any signature of call target.
Applies a given project function to each value emitted by the source
Observable, and emits the resulting values as an Observable.

<span class="informal">Like Array.prototype.map(),
it passes each source value through a transformation function to get
corresponding output values.</span>

<img src="./img/map.png" width="100%">

Similar to the well known Array.prototype.map function, this operator
applies a projection to each value and emits that projection in the output
Observable.

@example <caption>Map every every click to the clientX position of that click</caption>
var clicks = Rx.Observable.fromEvent(document, 'click');
var positions = clicks.map(ev => ev.clientX);
positions.subscribe(x => console.log(x));

@see {@link mapTo}
@see {@link pluck}

@return {Observable<R>} An Observable that emits the values from the source
Observable transformed by the given project function.
@method map
@owner Observable

(property) Observable<Response>.map: <T, R>() => any

Upvotes: 0

Views: 999

Answers (1)

Suraj Rao
Suraj Rao

Reputation: 29635

Observable.map takes only one callback function as parameter. You should put the error callback in subscribe() or use catch

 if(headers) {
            return this.http.get(this.baseUrl+url, {headers: headers}).map(response => {

            }).catch(err=>{});

        }

Upvotes: 3

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