What are observables and promises?

Related questions

1. What is the difference between mutable and immutable?
2. Is react js better than Angularjs?
3. Why are observables instead of promises?
4. Can observable can handle multiple events?
5. What is NGRX store?
6. Is single immutable data structure?
7. Which is better Redux or flux?
8. Why is ReactJS so popular?
9. Why react JS is faster?
10. Is Redux required for react?

Tags

1. #matter
2. #observable
3. #languages
4. #because
5. #callback
6. #often
7. #provides
8. #where
9. #promise
10. #allows
11. #events
12. #event
13. #called
14. #multiple
15. #handle
16. #features
17. #preferred
18. #doesn
19. #stream