This benchmark compares three different approaches to key-value data storage in JavaScript:

1. WeakMap:

   • Description: WeakMap is a collection of key/value pairs that allows only objects as keys. In a WeakMap, the keys are "weakly referenced," meaning if there are no other references to a key object, it can be garbage collected.
   • Pros:
     • It automatically cleans up memory when keys are no longer needed, providing better memory management.
     • Ideal for associating metadata to existing objects without modifying the objects directly.
   • Cons:
     • Only objects can be used as keys (no primitives).
     • The absence of methods to iterate or retrieve all entries can be limiting.

2. Symbol Property:

   • Description: Symbols are a primitive data type in JavaScript, generally used to create unique identifiers for object properties. By assigning a value to an object using a symbol as the key, it prevents accidental naming collisions.
   • Pros:
     • Provides unique and non-enumerable property keys, ensuring that they won't conflict with properties created by other parts of code.
   • Cons:
     • Difficult to manage as they do not easily allow checking for existence or enumeration.
     • Memory management is manual; if the object is referenced elsewhere, the memory will not be freed.

3. CustomWeakMap:

   • Description: This is a user-defined class that mimics the functionality of WeakMap using regular property access on objects. The class uses a relation key to store associated values.
   • Pros:
     • Allows customization and possible optimization of operations; for example, it directly alters object properties.
     • Offers similar functionality to the WeakMap, but the user has control over implementation and can optimize specific use cases.
   • Cons:
     • Lacks built-in memory management capabilities; it depends solely on the garbage collector behavior for the objects being manipulated.
     • Potential for memory leaks if not carefully managed.

Performance Comparison of Benchmark Cases

1. Set Operations

• WeakMap set: It recorded an execution rate of 102614104.0 operations per second. This implementation incurs overhead due to its internal structure and mechanics.
• Symbol Property set: This operation performed slightly better, at 173704560.0 operations per second, since it directly modifies the object property, making it less computationally intensive.
• CustomWeakMap set: Closely matches Symbol performance at 167226688.0. Its direct approach to property assignment balances well with similar operational speed.

2. Get Operations

• WeakMap get: This showed the worst performance at 97679648.0 operations per second, likely due to additional internal checks and structures.
• Symbol Property get: Performed better than WeakMap but slower than custom implementations at 153358800.0 operations per second.
• CustomWeakMap get: Achieved the best performance at 173829632.0 operations per second, benefiting from direct property access.

Conclusion and Alternatives

The results indicate that while WeakMap provides significant advantages in memory management, it may not perform as well as the direct approaches (using symbols or custom implementations). If memory management and automatic cleanup are not as critical for the application's logic, the custom WeakMap implementation and symbol properties offer competitive performance with the added advantage of flexibility in handling keys.

Other alternatives to consider for key-value data storage in JavaScript include using plain objects for simple mapping requirements, or third-party libraries such as Immutable.js or Lodash, which offer functional data structures that can provide performance benefits and extra functionality depending on your use case.