JavaScript Code

Maps

Map is a collection of key-value pairs, where keys are unique in a map.

Create a new Map

new Map() creates a new empty map.

let myMap = new Map();

We can also pass an array of key-value pairs, where each pair is an array with key as first element, and value as second element.

let myMap = new Map([
  ["apple", 20],
  ["banana", 30],
  ["cherry", 15]
]);

Add/Set Key-Value

Map.set(key, value) adds a new entry into the map with the given key and value. If the key if already present, then it sets the given value for the key.

let myMap = new Map();

myMap.set("apple", 20);
myMap.set("banana", 30);

for (let [key, value] of myMap) {
    console.log(`${key} - ${value}`);
}

Delete Key-Value

Map.delete(key) removes the entry with the given key, if present, from the map.

let myMap = new Map([
    ["apple", 20],
    ["banana", 30],
    ["cherry", 15]
]);

myMap.delete("banana");

for (let [key, value] of myMap) {
    console.log(`${key} - ${value}`);
}