WeakMap & WeakSet

What pattern does this code implement using WeakMaps?

const keyStorage = new WeakMap();
const valueStorage = new WeakMap();

class BiMap {
  set(key, value) {
    keyStorage.set(value, key);
    valueStorage.set(key, value);
  }
  
  getByKey(key) {
    return valueStorage.get(key);
  }
  
  getByValue(value) {
    return keyStorage.get(value);
  }
}

Simple key-value storage
Bidirectional mapping with garbage collection support
This code implements: 1) A bidirectional map where both keys and values can be looked up, 2) Automatic cleanup when either keys or values are garbage collected, 3) Memory-efficient two-way references between objects, 4) A pattern that maintains referential integrity while allowing garbage collection, 5) A solution for cases requiring reverse lookups without memory leaks, 6) Efficient object-to-object mapping with automatic cleanup, 7) A practical use of multiple WeakMaps for complex data structures, 8) A pattern that's particularly useful in object relationship management.
Caching system
Event handling

Next Question (18/20)