30. What is the purpose of the 'Set' object in JavaScript and how does it differ from an array?

Understanding the 'Set' Object in JavaScript

The Set object in JavaScript is a collection of values where each value must be unique. This means that no two values in a set can be the same. Unlike arrays, Set is specifically designed to handle unique data and provides a convenient way to manage collections of data without duplicates.

Key Characteristics of a Set:

• Uniqueness: All elements in a Set are unique. If you try to add a duplicate value, it will be ignored.
• Order of elements: The order of elements in a Set is based on the order of insertion.
• Data type independence: A Set can store any type of data, whether it be primitive values or object references.

Basic Usage:

Here is a simple example of how to create and use a Set:

const mySet = new Set();

// Adding values to the Set
mySet.add(1);
mySet.add(5);
mySet.add(5); // Duplicate value, will be ignored
mySet.add('Hello');

console.log(mySet); // Output: Set { 1, 5, 'Hello' }

// Checking the size of the Set
console.log(mySet.size); // Output: 3

// Checking if a value exists in the Set
console.log(mySet.has(5)); // Output: true

// Removing a value from the Set
mySet.delete(1);
console.log(mySet); // Output: Set { 5, 'Hello' }

Differences Between a Set and an Array:

• Uniqueness: Arrays can contain duplicate values, whereas Set enforces uniqueness.
• Methods: Set provides methods such as add(), delete(), and has(), which are not available on arrays. Arrays have methods like map(), filter(), and reduce() to manipulate data.
• Performance: Set operations like searching, adding, and deleting items have better average time complexity because they are implemented using hash tables.

Use Cases for Sets:

• Removing duplicates from an array:

  const numbers = [1, 2, 2, 3, 4, 4, 5];
  const uniqueNumbers = [...new Set(numbers)];
  console.log(uniqueNumbers); // Output: [1, 2, 3, 4, 5]

• Handling unique data collections: When you need to ensure that all elements in a collection are unique, a Set is the ideal data structure.

In summary, the Set object is a powerful feature in JavaScript when dealing with collections of unique items. Its distinct methods and properties make it an excellent choice for specific use cases involving unique data management.