const map = new Map();
const count = 100000;
for (let i = 0; i < count; ++i) {
map.set("test_"+i, i);
}
let val = map.entries().next().value;
//map.set(val[0], val[1] + 1);
let [[key, val]] = map;
//map.set(key, val + 1);
let val = map[Symbol.iterator]().next().value;
//map.set(val[0], val[1] + 1);
let val = Array.from(map)[0];
//map.set("test_0", val + 1);