Argument of type '1' is not assignable to parameter of type 'number[]'

Question

I am using Angular4 and currently started exploring Services of Angular4. I have done everything right in my dataServices class but still i am getting this error in argument ofobserver.next(1);\

Please tell me where i am wrong.

Error:

Argument of type '1' is not assignable to parameter of type 'number[]'

data.service.ts:

import { Injectable } from '@angular/core';
import { Observable } from 'rxjs/Observable';


@Injectable()

export class DataService{
    data: Observable<Array<number>>;

constructor(){

}
getData(){
    this.data = new Observable(observer =>{
        setTimeout(() =>{
            observer.next(1);
        }, 1000);

        setTimeout(() =>{
            observer.next(2);
        }, 2000);

        setTimeout(() =>{
            observer.next(3);
        }, 3000);

        setTimeout(() =>{
            observer.next('Hello');
        }, 4000);

        setTimeout(() =>{
            observer.complete();
        }, 5000);
    });

    return this.data;
    }
}

Answer 1

You wrote this type for data:

data: Observable<Array<number>>;

But you're trying to pass a number, not an array of numbers. So you can just change the type of data:

data: Observable<number>;