const inventory = new Map([
  ["sword", { qty: 3, value: 150 }],
  ["shield", { qty: 1, value: 200 }],
  ["potion", { qty: 5, value: 30 }],
]);

const upgraded = new Map(
  [...inventory.entries()]
    .filter(([, item]) => item.value >= 100)
    .map(([key, item]) => [key, { ...item, value: item.value * 2 }])
);

console.log(upgraded.size);
console.log(upgraded.get("sword").value);
console.log(upgraded.has("potion"));
console.log([...upgraded.keys()].join(", "));