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

In the code snippet, we used destructuring assignment to get the first element of the set and assign 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

In the code snippet, we skip the first element by adding a , 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 into 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 the set into an array and 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

In the code snippet we call the values method on the set to get an iterator.

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

Finally, we access 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