Set

Collection of elements that store unique elements.

A set of special type collections- a set of values, where each value may occur only once.

var set1 = new Set([10, 20, 30, 30, 40, 40]);
//it contains [10, 20, 30 ,40]

To add more values to set

var set1 = new Set([10, 20, 30, 30, 40, 40]);
set1.add(70);
console.log(set1);

let a = [1, 2, 1, 2, 1, 2, 8, 1, 9];
let num = new Set (a);
num.add(5);
console.log(num);

Properties:

new.Set([it])-//create set //it-iterable
Set.prototype.add(value)-//add value, return the set itself.
Set.delete(value) //remove value
Set.has(value) //return true if value exist
Set.size(value) //element count

Map

Map is a collection of keyed data items, just like an object but the difference is that map allow keys of any type.

Map is a collection of elements where each element is stored as a Key, value pair. You create your key whatever data type you want.

let city = [
['india', 'delhi'],
['gujrat', 'surat'],
['rajisthan', 'jaipur']
];
let newmap = new Map(city);
console.log(newmap);
console.log(newmap.get('india'));

Properties

new Map([it]) //create map
map.set(key, value) //store value by key
map.has(key) //return true if key exist
map.size //return current element count
map.get(key) //return val by key, undef if key does'nt exist in map.