How to Get the First Element of a Set in JavaScript

Get the First Element of a Set in JavaScript #

To get the first element of a Set, use destructuring assignment, e.g. const [first] = set. The destructuring assignment sets the variable to the first element of the Set.

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

const [first] = set;
console.log(first); // 👉️ 1

We used destructuring assignment to get the first element of the Set and assigned it to a variable.

We can get the second element of the Set in a similar way:

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

const [, second] = set;
console.log(second); // 👉️ 2

We skipped the first element by adding a comma , to the denote the place of the first element in the destructuring assignment.

We can also get the first element of a set using the spread syntax.

To get the first element of a set, use the spread syntax to convert the Set to an array and access the element at index 0, e.g. const first = [...set][0].

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

const first = [...set][0];
console.log(first); // 👉️ 1

We can iterate over a Set, so we can also convert one to an array to use the index to access the element at position 0.

A more long winded way to get the first element of a Set is to use the methods on the Set instance.

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

const values = set.values(); // 👉️ iterator
const obj = values.next() // 👉️ {value: 1, done: false}
const first = obj.value;
console.log(first); // 👉️ 1

We called the values method on the Set to get an iterator.

We then called the next method on the iterator to get an object containing the value of the first iteration.

Finally, we accessed the value property on the object to get the value of the first element in the Set.

Further Reading #

• How to Initialize a Set with Values in JavaScript
• Check if a Set contains a Value using JavaScript
• How to Check if two Sets are equal using JavaScript
• How to check if a Set is Empty in JavaScript
• How to sort a Set in JavaScript
• How to get the Length of a Set in JavaScript
• How to convert a Set to an Array in JavaScript
• How to Convert an Array to a Set in JavaScript
• Check if Object is of type Set in JavaScript