Design Patterns

Intermediate

Design patterns are typical solutions to common problems in software design. Each pattern is like a blueprint that you can customize to solve a particular design problem in your code.

Real World Applications

1. Creating reusable and maintainable code

2. Solving common software design problems

3. Improving code readability and documentation

4. Facilitating communication between developers

Practical Examples

Singleton Pattern

Ensures a class has only one instance and provides a global point of access to it.

Code Exampletypescript
class Singleton {
  private static instance: Singleton;
  
  private constructor() {}
  
  public static getInstance(): Singleton {
    if (!Singleton.instance) {
      Singleton.instance = new Singleton();
    }
    return Singleton.instance;
  }
}

Observer Pattern

Defines a one-to-many dependency between objects so that when one object changes state, all its dependents are notified and updated automatically.

Code Exampletypescript
interface Observer {
  update(data: any): void;
}

class Subject {
  private observers: Observer[] = [];
  
  attach(observer: Observer) {
    this.observers.push(observer);
  }
  
  notify(data: any) {
    this.observers.forEach(observer => observer.update(data));
  }
}

Related Topics

architecturereusabilitymaintainability