singleton

/**
 * GlobalMap implemented using Singleton pattern.
 *
 * Ensures only ONE Map instance exists
 * across the entire application.
 */

export default class GlobalMap {
  // Private static instance
  static #instance = null;

  /**
   * Returns the singleton Map instance.
   *
   * @returns {Map}
   */
  static getInstance() {
    // Create instance only once
    if (GlobalMap.#instance === null) {
      GlobalMap.#instance = new Map();
    }

    return GlobalMap.#instance;
  }
}

export default GlobalMap;


/**
 * // fileA.js
import GlobalMap from './GlobalMap';

const gbMap = GlobalMap.getInstance();
gbMap.set('count', 42);

-- Somewhere else in another file, executed after the first:

// fileB.js
import GlobalMap from './GlobalMap';

const gbMap = GlobalMap.getInstance();
console.log(gbMap.get('count')); // 42
 */