How do promises work in JavaScript?

Related questions

1. What are promises in angular?
2. What is promise and observable in angular?
3. What is the difference between put and post?
4. Are callbacks closures?
5. Why do we use promises?
6. What is protractor promise?
7. What is meant by Promise in Angularjs?
8. What are promises and observables in angular?
9. Does .then return a promise?
10. What is TypeScript promise?

Tags

1. #whatever
2. #reason
3. #constructor
4. #rejected
5. #eager
6. #callbacks
7. #handle
8. #promises
9. #value
10. #pending
11. #doing
12. #attach
13. #possible
14. #rejection
15. #fulfilled
16. #states
17. #promise
18. #users
19. #start
20. #meaning
21. #invoked