Create an observable from an Object along with a starting value

This is not possible with RxJS 5 by default because it can't observe object properties. There used to be Object.observe() but it's discontinued so you shouldn't use it.

However (a little self promo), I'm the author of rxjs-ds package that combines RxJS 5 with window.Proxy objects and lets you create observable data structures (I'm planing to use it for some experimantal React + Redux applications where you could manipulate state by just changing object properties).

So for example you could use it like this:

import { ObservableObject } from 'rxjs-ds';

const original = {
  name: 'myName',
  count: 0
};

// Create an observable object from `original`
const proxied = new ObservableObject(original);

const currentCount = proxied.proxy;
const events = proxied.events;

// Create the observer that notifies me when updating object properties
events.onSet.subscribe(console.log);

// Note that I'm in fact modifying `proxied.proxy` and not the original object
currentCount['name'] = 'Rincewind';
currentCount['name'] = 'Twoflower';
currentCount['count'] = 42;

You can see live demo here: https://jsfiddle.net/42vp7pmw/3/

This prints to console the following output:

{property: "name", oldValue: "myName", newValue: "Rincewind", target: {…}}
{property: "name", oldValue: "Rincewind", newValue: "Twoflower", target: {…}}
{property: "count", oldValue: 0, newValue: 42, target: {…}}

If think what you are looking for is:

import { BehaviorSubject } from 'rxjs/BehaviorSubject';
const subj = new BehaviorSubject('yourValueHere');
Observable<string> obs = subj.asObservable();
obs.subscribe(x => console.log(x));
//logs initial value
subj.next('nextValue');
//logs next value

A BehaviorSubject inherits from Observable and Observer. You could return a observable from your function/class while storing the subject and call next if the value changes. This emits the next value and all subscribers will be executed again.