📚Map

Map - JavaScript | MDN

// init
const map1 = new Map();

// set
map1.set('key1', 123123);
map1.set('key2', 234234);
map1.set(2, 333);

console.log('pair:')
for (let [key, val] of map1) {
    console.log(key, val);
}

console.log('get:');
console.log(map1.get(2));
console.log(map1.get('key1'));

console.log(map1.has('key2'));

console.log(Array.from(map1.keys()));
console.log(Array.from(map1.values()));

map1.clear();
for (let [key, val] of map1) {
    console.log(key, val);
}