❗️Что будет на выходе:

const createModule = (() => {
  const privateCache = new WeakMap();

  return function(name) {
    const state = { name, version: 1, active: true };
    privateCache.set(state, { accessCount: 0 });

    return {
      getInfo() {
        const meta = privateCache.get(state);
        meta.accessCount++;
        return `${state.name}@v${state.version}`;
      },
      getAccessCount() {
        return privateCache.get(state).accessCount;
      },
      upgrade() {
        state.version++;
        return this;
      }
    };
  };
})();

const mod = createModule("auth");
mod.upgrade().upgrade();
console.log(mod.getInfo());
console.log(mod.getAccessCount());

Ответ: auth@v3 1

JavaScript test | #JavaScript & Max