SOLVED I am trouble with a TypeScript error


Hey, I need help for a typescript error.

I am developing a login page and I try use an api for this authentication.

So I created a requestoptions object;

var requestOptions = new RequestOptions({headers:headers});

then I used that in a method


And It turned an error, here it is

Typescript Error
Argument of type 'RequestOptions' is not assignable to parameter of type '{ headers?: HttpHeaders | { [header: string]: string | string[]; }; observe?: "body"; params?: Ht...'. Types of property 'headers' are incompatible. Type 'Headers' is not assignable to type 'HttpHeaders | { [header: string]: string | string[]; }'. Type 'Headers' is not assignable to type '{ [header: string]: string | string[]; }'. Index signature is missing in type 'Headers'.

Thank you


where are you defining this?

The error message says that there is the problem - when you don’t read it already I would highly recommend doing that.:smirk:


Hello here is the defining;

let headers = new Headers();


var requestOptions = new RequestOptions({headers:headers});

Thanks for your reply


Try the ‘HttpClient’ instead, i think you are using the deprecated old method with the new headers.

constructor(@Inject('apiUrl') private apiUrl, public http: HttpClient) { }

If I understood you correctly, you recommend use it this way?


please try it, i have not tested it, but its worth a try,


This is the current constructor method already :slight_smile:


Sorry I meant HttpHeaders instead of header, I confused it with the httpclient.

You should use HttpClient and Http header.


I tried that :confused: it doesn’t work. I created a topic in stackoverflow. You can see updates from here :slight_smile:


looks like it got solved there, could you also report the solution for future reference here and mark the topic as solved?


It solved by without using requestOptions, just used headers on post method

let headers = new HttpHeaders();


Use that values in that

return,JSON.stringify({username,password}), { headers: headers })

But now I have StaticInjectorError[HttpClient] runtime error, so it’s not fully solved yet


add ‘HttpModule’ to your app.module.ts

import { HttpModule } from '@angular/http'; 
  declarations: [
  imports: [


I already did it, thanks for your reply it’s worked