main.ts

main.ts

import {Observable} from "rxjs";

//Creating new Datasource using that API.
let nums = [0,1,2,3,4,5,6,7,8,9];

//Now passed this array as datasource in observable.
let dataSource = Observable.from(nums);

//Creating observer

class customObserver{
    next(value){
        console.log(`Incoming Value:- ${value}`);
    }
    error(e){
        console.log(`Error Happend:- $(e)`);
    }
    complete(){
        console.log("We are done!!!");
    }
}

//Subscribing observer
dataSource.subscribe(new customObserver());