The Singleton pattern is a design pattern that ensures a class has only one instance throughout the application and provides a global access point to that instance. It helps provide a stricter control over global variables. It is useful when one needs to manage shared resources like database connections, external libs/sdks, application state or configuration settings.
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Database Connections: In database libraries, a Singleton can manage a shared connection to a database, ensuring that multiple parts of an app don't create unnecessary connections.
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Logging: A logging utility is a classic use of Singleton. It ensures a consistent way to log messages throughout the application.
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State Management on Frontend: Stores for managing global application state are often Singleton. For example, Redux Store in React Apps.
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SDK Clients: Cloud service SDKs (e.g., AWS SDKs) often use Singleton to manage credentials and service clients.