EN
TypeScript - How to use Map?
2
points
Map is a data structure that allows us to keep key-value pairs.
1. Create Map
let map = new Map<string, number>();
2. Map - set, get, size method example
// create map
let map = new Map<string, number>();
// set entities
map.set("Ann", 25);
map.set("Seth", 32);
map.set("Kate", 27);
// get entities
let value1 = map.get("Ann");
console.log("Ann age: " + value1); // Ann age: 25
let value2 = map.get("Seth");
console.log("Seth age: " + value2); // Seth age: 32
let value3 = map.get("Kate");
console.log("Kate age: " + value3); // Kate age: 27
// siz of map
let size = map.size;
console.log("map size: " + size); // map size: 3
Output:
Ann age: 25
Seth age: 32
Kate age: 27
map size: 3
Run this example online:
3. Most important methods of Map:
map.set()
- add key-value pair to Map
map.get()
- retrieve value by key from Map
map.delete()
- delete key-value pair by given key from Map
map.has()
- check if there is a value for given key - return true / false
map.size()
- size of the map, number of key-value pairs in Map
Note about
map.set()
method.
In other languages or self implemented data structures to add key-value pair to Map the method is named: put, add or set.