$ npx ts-node src/<folder>/<file-name>.ts
$ npx ts-node src/behavioral/Observer.ts

Design patterns

Creational:

• Singleton
• Factory Method
• Prototype
• Abstract Factory
• Object Pool
• Builder

Structural:

• Adapter
• Bridge
• Decorator
• Facade
• Proxy
• Composite
• Flyweight
• Private Class Data

Behavioral:

• Iterator
• Observer
• Momento
• Strategy
• Interpreter
• State
• Mediator
• Null Object
• Template method
• Command
• Visitor
• Chain of Responsibility