TypeScript Design Patterns for Modern Apps

As applications grow in complexity, the importance of robust architectural patterns becomes clear. TypeScript, with its advanced type system, provides unique ways to implement classic design patterns.

1. The Singleton Pattern in TS

Singletons ensure a class has only one instance and provide a global point of access to it.

class DatabaseConnection {
  private static instance: DatabaseConnection;

  private constructor() {}

  public static getInstance(): DatabaseConnection {
    if (!DatabaseConnection.instance) {
      DatabaseConnection.instance = new DatabaseConnection();
    }
    return DatabaseConnection.instance;
  }
}

2. The Factory Pattern

The Factory pattern is excellent for creating objects without specifying the exact class of object that will be created.

interface Logger {
  log(message: string): void;
}

class ConsoleLogger implements Logger {
  log(m: string) { console.log(m); }
}

class LoggerFactory {
  static createLogger(type: 'console' | 'file'): Logger {
    return new ConsoleLogger(); // Simplified
  }
}

Conclusion

Using these patterns not only makes your code cleaner but also makes it more predictable and easier to test.