Memory Management & Garbage Collection

Why is WeakMap appropriate for this caching implementation?

const userCache = new WeakMap();

function getUser(userObject) {
  if (!userCache.has(userObject)) {
    userCache.set(userObject, {
      name: userObject.name,
      accessCount: 0,
      lastAccess: Date.now()
    });
  }
  
  const userData = userCache.get(userObject);
  userData.accessCount++;
  userData.lastAccess = Date.now();
  
  return userData;
}

It's faster than using a regular Map
It allows string keys unlike regular Maps
It doesn't prevent the userObject keys from being garbage collected when no longer used elsewhere
WeakMap is appropriate here because it doesn't prevent garbage collection of keys: 1) It holds weak references to the userObject keys, allowing them to be collected when no longer referenced elsewhere, 2) This prevents memory leaks that would occur with a regular Map, which would keep all userObjects in memory indefinitely, 3) The cache automatically 'cleans itself' as objects become unreachable, 4) This creates a self-managing cache that follows the lifecycle of the key objects, 5) It's ideal for this metadata/caching scenario where cache entries should expire with their associated objects, 6) No explicit cache invalidation is needed to prevent memory leaks, 7) The tradeoff is that WeakMap keys must be objects, not primitive values, 8) This demonstrates a memory-conscious design pattern for object-related caching.
It automatically expires cache entries after a certain time

Next Question (32/40)