of observable in promise code example

Example 1: promise to observable typescript

import { from } from 'rxjs';
const observable = from(promise);

Example 2: understanding Observable.create(

import { Observable } from "rxjs/Observable";

var observable = Observable.create(function subscribe(observer) {
    observer.next('Hey guys!')
})

// OR 

var observable = Observable.create((observer:any) => {
    observer.next('Hey guys!')
})