const regularMap = new WeakMap();
const obj = {};
regularMap.set(obj, true);
const manyKeysWeakMap = new ManyKeysWeakMap();
const date = new Date();
manyKeysWeakMap.set([obj, date], true);

const handlers = new ManyKeysWeakMap();
handlers.set([element, sub1], fn1);
const someOptions = {passive: true};
handlers.set([element, sub2, someOptions], fn2);

const ManyKeysWeakMap = require('many-keys-weakmap');
const groups = new ManyKeysWeakMap();
groups.set([header, admin], true);
groups.set([target, tools], [1, 'any value is supported']);
const key1 = {};
const keyA = {};
const keyB = {};
const data = new ManyKeysWeakMap([
	[[key1], 'value'],
	[[keyA, keyB], new Date()]
]);
data.get([key1]);
// => 'value'
data.get([keyA, keyB]);
// => date Object
data.get([{}]);
// => undefined
for (const [keys, value] of data) {
	console.log(keys);
	console.log(value);
}
// => [key1]
// => 'value'
// => [key1, key2]
// => date Object