Patterns of JavaScript: Singleton
Explained by video game levels
Singletons are handy when you need to coordinate system-wide actions from one place—for example, database connection pools.
Singletons reduce the need for global variables, which is critical in JavaScript because it limits namespace pollution and name collisions.
Other patterns, like Factory, Prototype, and Facade, are often implemented as singletons.
Singleton Pattern in a Nutshell
In the Singleton Pattern, there can only be one instance of an object at a time. A singleton is one instance of something.
When & Why Use the Singleton Pattern
Take a level manager as a good example.
The manager manages every level of the entire application. Very handy when you need to coordinate system-wide actions based on that level.
Initialize the player, spawn monsters, set up the UI, and so on. Besides, the player can only be in one playable level simultaneously. Hence it would be best if you had a single manager, not multiple.
Rule of thumb: Take the singleton if there can only be one of a kind.
