In this chapter, we covered the paradigm of promise and the concept behind it. We have covered the conceptual knowledge of promise, deferred, common sequences of promise, and how promise helps in decoupling the business logic and application logic. We have also covered the relation between promise and event emitters and the idea behind it.

Due to the virtue of this chapter, we are now able the select which promise library we should use on the basis of our knowledge gained.

In our next chapter, we will be looking at the implementation of promise in different programming languages and will examine the ease they are bringing for the developers and end users.