WeakMap.prototype.set()

const weakmap = new WeakMap();
const object1 = {};
const object2 = {};
weakmap.set(object1, "foo");
weakmap.set(object2, "bar");
console.log(weakmap.get(object1));
// Expected output: "foo"
console.log(weakmap.get(object2));
// Expected output: "bar"

set(key, value)

const wm = new WeakMap();
const obj = {};
// Add new elements to the WeakMap
wm.set(obj, "foo").set(window, "bar"); // chainable
// Update an element in the WeakMap
wm.set(obj, "baz");
// Using a non-registered symbol as key
const sym = Symbol("foo");
wm.set(sym, "baz");
wm.set(Symbol.iterator, "qux");