rxjs - What is the Difference between new Observable and of or from?

Question

What is the Difference between new Observable and observable created from of or from?

of([1, 2, 3]).subscribe(x => console.log(x));

from([1, 2, 3]).subscribe(x => console.log(x));

vs new Observable()

What is the main difference between the above two way of creating observables?

I have read this, but it's not yet convincing! what is the difference between "new Observable()" and "of()" in RxJs

I'm not asking difference between of and from. I'm asking difference between either (of or from) from new Observable()

Answer 1

Essentially, the observable creation functions of, from, and others simply create a new Observable() with specific behavior.

So, the only difference between new Observable() and the creator fuctions is the actual behavior.

For example, here is what the of() function looks like (simplified):

export function of<T>(...array: Array<T>): Observable<T> {
  return new Observable<T>(subscriber => {
    for (let i = 0; i < array.length && !subscriber.closed; i++) {
      subscriber.next(array[i]);
    }
    subscriber.complete();
  });
}

You can see that new Observable() is called within the of() function.