of(...items): Returns an Observable instance that synchronously delivers the
values provided as arguments.
Example:
// Create simple observable that emits three values
const myObservable = of(1, 2, 3);
// Create observer object
const myObserver = {
next: (x: number) => console.log('Observer got a next value: ' + x),
error: (err: Error) => console.error('Observer got an error: ' + err),
complete: () => console.log('Observer got a complete notification'),
};
// Execute with the observer object
myObservable.subscribe(myObserver);
// Logs:
// Observer got a next value: 1
// Observer got a next value: 2
// Observer got a next value: 3
// Observer got a complete notification