Js Map Methods in JavaScript
?? JavaScript Map Methods
A Map is a collection of key-value pairs where keys can be any data type (objects, functions, primitives). It remembers the insertion order of keys.
? Creating a Map
const myMap = new Map();? Common Map Methods
| Method | Description | Example |
|---|---|---|
set(key, value) | Adds or updates a key-value pair | myMap.set('name', 'Alice'); |
get(key) | Retrieves value by key | myMap.get('name'); // 'Alice' |
has(key) | Checks if a key exists | myMap.has('name'); // true |
delete(key) | Removes a key-value pair | myMap.delete('name'); |
clear() | Removes all entries | myMap.clear(); |
size (property) | Returns number of entries | myMap.size; |
keys() | Returns an iterator of all keys | myMap.keys(); |
values() | Returns an iterator of all values | myMap.values(); |
entries() | Returns an iterator of [key, value] pairs | myMap.entries(); |
forEach(callback) | Calls callback for each [key, value] pair | myMap.forEach((val, key) => console.log(key, val)); |
? Example Usage
const map = new Map();// Add entriesmap.set('name', 'John');map.set(1, 'one');map.set(true, 'yes');// Get valueconsole.log(map.get('name')); // John// Check existenceconsole.log(map.has(1)); // true// Size of mapconsole.log(map.size); // 3// Iterate over map entriesfor (const [key, value] of map.entries()) { console.log(`${key} => ${value}`);}? Output
Johntrue3name => John1 => onetrue => yesWould you like examples on how to convert Maps to arrays or JSON?
