How to check if a set is empty - JavaScript

In this article we will learn how to check if set is empty in JavaScript.

It is very common to check if set is empty in JavaScript in JavaScript.

Problem

Now we have a problem which is that we want to check if set is empty.

Imagine we have set like this:

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

And we want to check if this set is empty or not.

Expected Output

false

How to solve this problem?

The solution to this problem is easy, and fortunately, there is a built-in function in the set that calculates the number of elements in the set, called size().

Check if set is empty using size method

As we said before, we can use size() method to check if set is empty or not.

Example

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

if (set.size === 0) {
    console.log('Set is empty');
    console.log(true);
} else {
    console.log('Set is not empty');
    console.log(false);
}

Output

Set is not empty
false

Well, now you will probably use these codes more than once, so let's do a function called isEmpty.

function isEmpty(set) {
    // If set is empty
    if (set.size === 0) {
        return true;
    }

    // Otherwise
    return false;
}

const set1 = new Set([1, 2, 3, 4]);
const set2 = new Set([]);

console.log(isEmpty(set1));
console.log(isEmpty(set2));

Output

false
true

Thank you for reading

Thank you for reading my blog. 🚀