Dictionaries

As you have learned, a set is a collection of distinct elements (nonrepeated elements). A dictionary is used to store [key, value] pairs, where the key is used to find a particular element. A dictionary is very similar to a set; a set stores a [key, key] collection of elements, and a dictionary stores a [key, value] collection of elements. A dictionary is also known as a map.

In this chapter, we will cover some examples of how to use the dictionary data structure in the real world: a dictionary itself (the words and their definitions) and an address book.

Creating a dictionary

Similarly to the Set class, ECMAScript 6 also contains an implementation of the Map class, also known as a dictionary.

The class we will implement in this chapter is based on the Map implementation of ECMAScript 6. You will notice that it is very similar to the Set class (but instead of storing a [key, key] pair, we will store a [key, value] pair).

This is the skeleton of our Dictionary class:

function Dictionary...