singleton-pattern

The singleton pattern in JavaScript ensures only one instance of a class exists. Use it to manage global state, centralized configuration, or shared resources like logging and caching across multiple modules.

To implement a singleton for global state, create a JavaScript class that checks for an existing instance upon instantiation and returns it. You can then export a frozen instance to prevent any further modification.

Yes, you can use a singleton for centralized configuration across modules. It provides a single global access point, ensuring that all parts of your application reuse the same configuration instance without creating duplicates.

A frozen singleton instance prevents unwanted state modification by locking the exported object. This ensures the shared global state or configuration remains read-only and cannot be accidentally altered by other modules importing the instance.

A limitation of the singleton pattern for shared resources is the potential introduction of tight coupling across modules. Overusing singletons for global state can make dependencies hidden and complicate unit testing due to shared, persistent state.