Set in JavaScript (Live Playground)

In JavaScript, the Set data structure allows you to store unique values of any type, including primitive values and object references. A Set object can be used to store and manipulate collections of distinct elements without duplicates. In this tutorial, we will explore the Set data structure and its methods.

Creating a Set

To create a Set, use the Set constructor. You can create an empty set or initialize it with an iterable object, such as an array:

const emptySet = new Set();

const numbers = new Set([1, 2, 3, 4, 5]);

numbers.forEach(num => console.log(num));

Live Playground, Try it Yourself

Adding Elements

To add elements to a set, use the add method:

const fruits = new Set();

fruits.add('apple');
fruits.add('banana');
fruits.add('orange');
fruits.add('apple'); // This won't be added since 'apple' is already in the set.

Removing Elements

To remove a specific element from a set, use the delete method:

fruits.delete('banana'); // Returns true if the element is found and removed, otherwise false.

To remove all elements from a set, use the clear method:

fruits.clear();

Checking for Elements

To check if a set contains a specific element, use the has method:

fruits.has('apple'); // Returns true if the element is in the set, otherwise false.

Set Size

To get the number of elements in a set, use the size property:

fruits.size; // Returns the number of elements in the set.

Iterating Over a Set

You can use the forEach method or a for...of loop to iterate over a set:

fruits.forEach(fruit => console.log(fruit));

for (const fruit of fruits) {
  console.log(fruit);
}

Live Playground, Try it Yourself

Conclusion

In this tutorial, we've covered the Set data structure in JavaScript, which allows you to store unique values efficiently. We've explored how to create a set, add and remove elements, check for elements, determine set size, and iterate over a set. Sets can be particularly useful when you need to store and manipulate collections of distinct elements without duplicates.