Map() in JavaScript

Map() is built-in object in JavaScript that allows you to store key value pairs. It is a part of ES6 release.

It is more like a object with better performance and following features.

Key-value pairs: Map()provide flexibility to choose any datatype for key-value pair, unlike object which only supports string type of key.

const myMap=new Map()
myMap.set(1,'One')
myMap.set(true,'exist')
console.log(myMap)

//output { 1 => 'One', true => 'exist' }

Map Preserves Insertion Order: It preserve the order of element on their insertion, in other words you can say it maintain the order of values getting inserted.

CRUD operation on map: There are multiple functions available for doing crud option as mention below
1.get()
2. set()
3. delete()
4.has()
and one property to calculate the size of Map()object

const myMap=new Map()
myMap.set(1,'One')
myMap.set(true,'exist')

console.log(myMap)

const mapValue=myMap.get(1)
console.log(mapValue)

myMap.delete(true)
console.log(myMap)

console.log(myMap.has(1))

console.log(myMap.size)

output(NodeJs)
 Map(2) { 1 => 'One', true => 'exist' }
One
Map(1) { 1 => 'One' }
true
1

Best Use Cases:
1. Frequent Addition/Deletion of key-value pairs.
2. As a object alternative.
3. Where you need a specific type of key-value pairs.
4. You want to maintain the order as object shuffle the element or object don’t don’t have any order.

Note:
1. For iterating over the map, we can either use forEach or for…of.
2. Map() don’t have key by default
Map is implemented differently from regular objects:

• It does not inherit keys from Object.prototype.
• It stores keys explicitly without prototype chaining.

3. Mapis more secure than object.
4. Map()is a iterable but object is not directly iterable.
5.Map() no built-in support for serialization and parsing.

I hope this article help you understand Map()

Thanks and Regards
Saurav Kumar Sharma