The ES2015 Map class

ECMAScript 2015 introduced a Map class as part of the JavaScript API. We developed our Dictionary class based on the ES2015 Map class.

Note

You can take a look at the details of the ECMAScript 2015 Map class implementation at: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map (or http://goo.gl/dm8VP6).

Let's learn how we can use the native Map class, as well. Let's use the same examples we used to test our Dictionary class:

const map = new Map();

map.set('Gandalf', '[email protected]');
map.set('John', '[email protected]');
map.set('Tyrion', '[email protected]');

console.log(map.has('Gandalf')); // true
console.log(map.size); // 3
console.log(map.keys()); // MapIterator {"Gandalf", "John", "Tyrion"}
console.log(map.values()); // MapIterator {"[email protected]", "[email protected]", "[email protected]"}
console.log(map.get('Tyrion')); // [email protected] 

The difference between our Dictionary class and the ES2015 Map class is that the...