Map in javascript
Table of Content:
In JavaScript, the Map
object is a built-in data structure that allows you to store key-value pairs. It is similar to an object but provides some additional features and advantages. Here's an example of how you can use a Map
:
// Creating a Map let myMap = new Map(); // Adding key-value pairs myMap.set('name', 'Rumman'); myMap.set('age', 25); myMap.set('isStudent', true); // Getting values console.log(myMap.get('name')); // Output: Rumman console.log(myMap.get('age')); // Output: 25 console.log(myMap.get('isStudent')); // Output: true // Checking if a key exists console.log(myMap.has('gender')); // Output: false // Deleting a key-value pair myMap.delete('isStudent'); // Iterating over key-value pairs for (let [key, value] of myMap) { console.log(`${key}: ${value}`); } // Output: // name: Rumman // age: 25
Here are some key points about Map
:
-
Keys can be of any data type: Unlike object keys which are converted to strings,
Map
keys can be of any data type, including objects and primitive values. -
Order of insertion is maintained:
Map
objects maintain the order of key-value pairs based on the order of insertion. -
Iterable: You can easily iterate over the keys or values of a
Map
using loops or methods likeforEach
. -
Size property: The
size
property indicates the number of key-value pairs in theMap
.
Using Map
is especially useful when you need to associate values with keys and perform operations like adding, deleting, and checking for the existence of keys in a more straightforward and reliable manner compared to using plain objects.