Learning JavaScript Data Structures and Algorithms - Second Edition

Chapter 7.  Dictionaries and Hashes

In the previous chapter, you learned about sets. In this chapter, we will continue our discussion about data structures that store unique values (nonrepeated values) using dictionaries and hashes.

Sets, dictionaries, and hashes store unique values. In a set, we are interested in the value itself as the primary element. In a dictionary (or map), we store values in pairs as [key, value]. The same goes for hashes (they store values in pairs, such as [key, value]); however, the way that we implement these data structures is a little bit different, as we will see in this chapter.

Dictionaries

As you have learned, a set is a collection of distinct elements (nonrepeated elements). A dictionary is used to store [key, ...