import { mergeWeakMaps, mergeWeakSets } from 'weak-merge'

const [a, b, c, d] = [{}, {}, {}, {}]

const weakSet1 = new WeakSet([a, b])
const weakSet2 = new WeakSet([c])

const mergedWeakSet = mergeWeakSets(weakSet1, weakSet2)

console.log([a, b, c].map(key => mergedWeakSet.has(key)))
//=> [ true, true, true ]

mergedWeakSet.delete(a)
console.log(mergedWeakSet.has(a))
//=> false

console.log(weakSet1.has(a))
//=> true

mergedWeakSet.add(d)
console.log(mergedWeakSet.has(d))
//=> true

console.log(weakSet1.has(d))
//=> false

const weakMap1 = new WeakMap([
  [a, 1],
  [b, 2],
])
const weakMap2 = new WeakMap([[c, 3]])

const mergedWeakMap = mergeWeakMaps(weakMap1, weakMap2)

console.log([a, b, c].map(key => mergedWeakMap.get(key)))
//=> [ 1, 2, 3 ]

mergedWeakMap.delete(a)
console.log(mergedWeakMap.has(a))
//=> false

console.log(weakMap1.has(a))
//=> true

mergedWeakMap.set(a, 5)
console.log(mergedWeakMap.get(a))
//=> 5

console.log(weakMap1.get(a))
//=> 1