Use the size property to get the length of a Set in JavaScript. The size accessor property returns the number of elements in a Set object.
mySet.size;Note: the size property is read-only and can’t be changed by the user.
Javascript set length
Simple example code.
<!DOCTYPE html>
<html>
<body>
<script>
const set = new Set(['a', 'b', 'c']);
console.log(set.size);
set.add('d');
set.add('e');
console.log(set.size);
</script>
</body>
</html>
Output:
More example
const set1 = new Set();
const object1 = {};
set1.add(42);
set1.add('forty two');
set1.add('forty two');
set1.add(object1);
console.log(set1.size); // 3This property, unlike Array.prototype.length, is read-only, which means that you can’t change it by assigning something to it:
mySet.size = 5;
mySet.size; // 4
In strict mode it even throws an error:
TypeError: Cannot set property size of #<Set> which has only a getterDo comment if you have any doubts or suggestions on this Js set topic.
Note: The All JS Examples codes are tested on the Firefox browser and the Chrome browser.
OS: Windows 10
Code: HTML 5 Version