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 of observer.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

this.data is an Array of numbers, not a single number. Push your values to this.data instead.

Answer 2

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>;