JavaScript Set Methods

Overview of Set Methods and Properties

• new Set()
• add()
• clear()
• delete()
• entries()
• forEach()
• has()
• keys()
• values()
• size

The new Set() Method

You can create a new set by passing an array to the new Set() constructor. This allows for the initialization of a set with a collection of elements.

The add() Method

When using the add() method, only unique values are stored in a set. If you attempt to add a duplicate element, the existing set remains unchanged as it does not save multiple instances of the same value.

The size Property

The size property returns the number of unique elements within a set.

Listing Set Elements

To list all elements in a set, you can use a for..of loop, which iterates over each value.

The has() Method

The has() method checks for the existence of a specified value within a set, returning true if the value is found.

The forEach() Method

The forEach() method executes a provided function once for each value contained in the set.

The values() Method

The values() method provides an Iterator object, which allows access to all the values stored in a set.

The keys() Method

In sets, the keys() method returns an Iterator object with the set's values. Since sets do not have keys, this method functions identically to values().

The entries() Method

The entries() method returns an Iterator containing [value, value] pairs. Though traditionally designed to return [key, value] pairs, in sets, both elements are identical, aligning their behavior with maps.

Learn More

For further reading, explore additional topics such as JavaScript Sets, Set Logic, Weak Sets, Set Reference, and JavaScript Maps.