Map.prototype.set()

const map = new Map();
map.set("bar", "foo");
console.log(map.get("bar"));
// Expected output: "foo"
console.log(map.get("baz"));
// Expected output: undefined

set(key, value)

const myMap = new Map();
// Add new elements to the map
myMap.set("bar", "foo");
myMap.set(1, "foobar");
// Update an element in the map
myMap.set("bar", "baz");

// Add new elements to the map with chaining.
myMap.set("bar", "foo").set(1, "foobar").set(2, "baz");