The Singleton Pattern is a design pattern that restricts the instantiation of a class to a single "instance." This is particularly useful when you need a global point of access to a shared resource or a central state.

Why use a Singleton?

🎯 Single Point of Control: Centralize management for things like app configurations, logging, or database connections.

🌍 Global State: Maintain data that needs to be accessible across different, unrelated parts of an application.

🚀 Resource Efficiency: Prevent duplicate initialization of heavy objects to save memory and processing power.

💾 Centralized Caching: Implement a shared cache where all modules read from and write to the same data store.

Your Task: Implement a module named GlobalMap. This module should export an object containing a getInstance() method. This method must always return the exact same Map instance, regardless of how many times or from where it is called.

💡 Examples

// In Module A
import GlobalMap from './GlobalMap';
const cacheA = GlobalMap.getInstance();
cacheA.set('session_id', '12345');

// In Module B
import GlobalMap from './GlobalMap';
const cacheB = GlobalMap.getInstance();

console.log(cacheB.get('session_id')); // Output: '12345'
console.log(cacheA === cacheB);        // Output: true