Applying Maps to Real-World Challenges in JavaScript

Hello there! In this lesson, we will apply Maps to real-world challenges. Our focus will be on solving tasks such as cataloging books in a library, counting votes in an election, and tracking inventories.

Suppose you're asked to manage the cataloging of books in a library. Here, the book ID serves as the key, while the details of the book, such as the title, author, and year of publication, are stored as values. This approach allows us to add, search for, and remove books from our library catalog using just a few lines of JavaScript code.

// Initializing a Map
let libraryCatalog = new Map();

// Details of a book
let bookId = "123";
let bookDetails = new Map();
bookDetails.set("title", "To Kill a Mockingbird");
bookDetails.set("author", "Harper Lee");
bookDetails.set("year_published", "1960");

libraryCatalog.set(bookId, bookDetails);  // Adding a book to library catalog, where value itself is a Map

// Searching for a book
if (libraryCatalog.has(bookId)) {
    let details = libraryCatalog.get(bookId);
    console.log(`Title: ${details.get("title")}, Author: ${details.get("author")}, Year Published: ${details.get("year_published")}`);
}

libraryCatalog.delete(bookId);  // Removing a book from the library

As you can see, Maps make the task of cataloging books in the library simpler and more efficient. You can dynamically add a new book with its unique ID, retrieve its information, and even remove it if necessary.

Imagine a scenario in which we need to count votes in an election. We employ a Map, where each name is a unique key, and the frequency of that name serves as the associated value. Let's write some JavaScript code to better understand this.

let votesList = ["Alice", "Bob", "Alice", "Charlie", "Bob", "Alice"];  // Cast votes
let voteCounts = new Map();  // Initializing a Map

// Counting the votes
for (let name of votesList) {
    voteCounts.set(name, (voteCounts.get(name) || 0) + 1);
}

for (let [candidate, count] of voteCounts) {
    console.log(`${candidate}: ${count}`);
}
// Prints: Alice: 3, Bob: 2, Charlie: 1

Maps facilitate the efficient counting of votes. Using the Map, we can iterate over the votes, increment counts, and ultimately print the results in a straightforward and efficient manner.