Sets in JavaScript¶

A Set is a collection of unique values of any type, whether primitive values or object references.

Each value can only occur once within the set.

Creating a Set¶

You can create a Set using the new Set() syntax.

let set = new Set();

Adding Values¶

The add method is used to add a value to the set. If the value is already in the set, it does not get added again since all values in a set must be unique.

set.add('value1');

Checking Values¶

The has method is used to check if a value exists in the set.

console.log(set.has('value1'));  // Outputs: true

Size of a Set¶

The size property returns the number of values in the set.

console.log(set.size);  // Outputs: 1

Deleting a Value¶

The delete method removes a value by its value.

set.delete('value1');
console.log(set.has('value1'));  // Outputs: false

Removing All Values¶

The clear method removes all values from the set.

set.clear();
console.log(set.size);  // Outputs: 0

Iterating Over a Set¶

You can use for...of loop or forEach method to iterate over a Set. It returns values in the insertion order.

set.add('value1');
set.add('value2');

for (let value of set) {
    console.log(value);
}

// OR

set.forEach(function(value) {
    console.log(value);
});

Converting a Set to an Array¶

You can convert a Set to an Array using the spread operator (...).

let array = [...set];