Interview Study - TypeScript

1. What are the benefits of using TypeScript over JavaScript for backend development?

1. TypeScript offers static typing, catching errors at compile-time, enhancing code readability, maintainability, and IDE support, which fosters robustness and scalability in backend development.

1. Explain the concept of static typing in TypeScript and how it improves code quality and maintainability.

1. Static typing in TypeScript enforces variable types at compile-time, reducing runtime errors, enhancing code documentation, and facilitating refactoring, ultimately improving code quality and maintainability in backend projects.

1. How do you handle type checking in TypeScript when dealing with external libraries or APIs that lack type definitions?

1. In TypeScript, handling type checking for libraries or APIs without type definitions often involves using type assertions, type guards, or creating custom type definitions to ensure type safety and maintain code integrity.

1. Discuss some of the key features of TypeScript that make it well-suited for building scalable backend systems.

1. TypeScript's features like static typing, interfaces, generics, and strict null checks enable developers to write cleaner, safer, and more maintainable code, making it ideal for constructing scalable backend systems.

1. Can you explain the difference between interfaces and types in TypeScript? When would you use one over the other in a backend project?

1. In TypeScript, interfaces define contract-like structures for objects, while types encompass a broader range of data types. Interfaces are preferable for defining shapes of objects, whereas types are suitable for defining aliases for data types in backend projects.

1. How does TypeScript support Object-Oriented Programming (OOP) principles, and how would you apply these principles in a backend codebase?

1. TypeScript supports OOP principles through classes, inheritance, encapsulation, and polymorphism, facilitating modular and reusable code organization in backend applications, promoting maintainability and extensibility.

1. What are generics in TypeScript, and how do they contribute to writing reusable and type-safe code? Can you provide an example of using generics in a backend application?

1. Generics in TypeScript enable writing reusable, type-safe code by allowing the creation of functions and data structures that can work with any data type. For example, creating a generic repository class for database operations in a backend application.

1. How would you handle asynchronous operations in TypeScript, especially in the context of backend APIs or services?

1. Asynchronous operations in TypeScript backend, such as database queries or HTTP requests, are typically handled using async/await syntax or promises to ensure non-blocking execution and efficient resource utilization.

1. Discuss some common design patterns you've used in TypeScript backend development and explain when and why you would use them.

1. Common design patterns like Dependency Injection, Singleton, Factory, and Observer are utilized in TypeScript backend development to promote code reusability, scalability, and maintainability, depending on specific use cases and requirements.

1. Can you explain the concept of decorators in TypeScript and provide an example of how you might use them in a backend application, such as for middleware or authentication?

1. Decorators in TypeScript allow adding metadata or behavior to classes, methods, or properties at runtime, making them suitable for implementing cross-cutting concerns like logging, validation, or authentication in backend applications.

1. Describe your experience with unit testing TypeScript backend code. What tools and libraries do you prefer for testing, and how do you ensure adequate test coverage?

1. Experience in unit testing TypeScript backend code involves using frameworks like Jest or Mocha along with libraries like Chai or Sinon for assertions and mocks. Comprehensive test suites ensure adequate coverage, validating code functionality and preventing regressions.