TypeScript: 5 Essential Interview Questions

TypeScript, a superset of JavaScript, has become a cornerstone in modern web development, offering type safety and enhanced code structuring capabilities. As more companies adopt TypeScript for their projects, understanding its nuances and features is crucial for developers looking to excel in this environment. Below, we explore five critical TypeScript interview questions, complete with code examples, to help you prepare for your next job interview.

What is TypeScript and how does it differ from JavaScript?

Explanation: TypeScript is a statically typed programming language developed and maintained by Microsoft. It is a superset of JavaScript, meaning that any valid JavaScript code is also valid TypeScript code. The key difference lies in TypeScript’s static typing feature, which allows for checking the type of a variable at compile time.

Code Example:

How do you define and use enums in TypeScript?

Explanation: Enums (enumerations) are a feature in TypeScript that allows for defining a set of named constants. Using enums can make it easier to handle sets of related values more efficiently and with less error-pronality.

Code Example:

Explain the concept of interfaces in TypeScript. How are they different from classes?

Explanation: Interfaces in TypeScript are used to define the structure of an object, specifying the expected form of an entity. Interfaces are purely for declarations and cannot include implementation details. Unlike classes, they are not compiled to JavaScript; they are used by TypeScript for type checking.

Code Example:

How do you implement function overloading in TypeScript?

Explanation: Function overloading in TypeScript allows multiple functions to have the same name but different parameter types and/or counts. TypeScript achieves this through the signature of the functions, enabling calling the same function in different ways.

Code Example:

Describe generics in TypeScript and provide an example of their use.

Explanation: Generics provide a way to create reusable components while maintaining type safety. They allow a component to work over a variety of types rather than a single one.

Code Example:

Through these questions and examples, we’ve explored fundamental aspects of TypeScript that are crucial for both beginners and experienced developers. Understanding these concepts will not only help you in interviews but also in writing more efficient and error-free code.