How to delete first element of a set - JS

In this article we will learn how to delete first element of a set.

It is very common to delete first element of a set in JavaScript.

Problem

Now we have a problem, which is that we want to delete the first element of a set.

Now let's define a set like this:

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

console.log(set);
// Set(5) { 1, 2, 3, 4, 5 }

And we only want to delete the first element, so the output becomes like this:

Set(4) { 2, 3, 4, 5 }

How to solve this problem?

Fortunately, we have a built-in function that deletes elements from the set called delete.

Delete first element using delete method

We can use delete() method to delete first element of set.

Example

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

// Delete element
set.delete(1);

// Print the result:
console.log(set);

Output

Set(4) { 2, 3, 4, 5 }

Well, now what if I want to delete the first element and I don't know its key! What do I do?

Delete the first element of the set dynamically

Now I will answer the previous question, if you want to delete the first element and you don't know its key.

You can use Array.from() to get all the element in an array and then you can get first element easily.

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

// Array with elements
const array = Array.from(set);

// First element
const firstEle = array[0];

// Print
console.log(firstEle);

Output

1

Now that we get the first element, we can delete it using delete.

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

// Array with elements
const array = Array.from(set);

// First element
const firstEle = array[0];

// Delete first element by his key `[0]`
set.delete(firstEle);

// Print
console.log(set);

Output

Set(4) { 2, 3, 4, 5 }

Thank you for reading

Thank you for reading my blog. 🚀