12 Best TypeScript Interview Questions in 2023
Need to hire TypeScript developers? Then, you need the best TypeScript interview questions. And today, we share 12 questions you can use right away. Want to learn more? Read on!
But how do you choose the right TypeScript developer? Here below are our 12 top Typescript interview questions for junior and senior developers.
Beginner TypeScript interview questions
What interview questions should you ask junior developers? These questions are ideal for less experienced candidates who don’t have as much in-depth technical knowledge compared to more senior candidates.
This language also lets you define your own types (string, number, and Boolean) in an object-oriented manner. The compiler then checks your code against those types and flags problems before it moves on to a production environment.
2. What are the advantages of TypeScript?
TypeScript is simple, easy to learn, and fast. It’s expressive and has, therefore, less syntactical clutter. TypeScript is also easy to debug thanks to its advanced debugging features that focus on catching logical errors before compile time.
4. What are the most important TypeScript features?
The most important TypeScript features are:
ES6 features: Includes most features of planned ECMAScript 2015, such as Arrow functions.
Cross-platform: Its compiler can be installed on any operating system, including Windows, Linux, and macOS.
Static type-checking: TypeScript helps type checking at compile time by using static typing. This enables you to find compile-time errors while you’re writing the code without running the script.
Object-oriented language: TypeScript offers standard OOP features like interfaces, modules, and classes.
DOM Manipulation: TypeScript can be used to manipulate the DOM for adding or removing client-side web page elements.
Advanced TypeScript interview questions
What are some more advanced TypeScript interview questions? Here are questions to ask senior TypeScript developers.
5. What are type assertions in TypeScript?
Type assertion works in the same way as typecasting in other languages, essentially as a soft version of typecasting. What it means is that type assertion suggests that the compiler sees the variable as a certain type, but it doesn’t force it into that mold. However, type checking and restructuring of data, which are possible in languages like C# and Java, are not possible in TypeScript. Type assertion doesn’t have an impact on runtime and it’s used purely in the compiler.
6. How do you use TypeScript Mixins?
Mixins are inheritance that works in the opposite direction. They allow you to build new classes by combining simpler partial class setups from previous classes. For instance, instead of class A extending class B to gain functionality, class B takes from class A and returns a new class with additional functionality.
7. What’s a .map file? How do you use it?
8. What is JSX in TypeScript?
9. What are Arrow or lambda functions?
Arrow functions in TypeScript are similar to lambda functions in other languages. This function is a shorthand syntax for defining function expressions of anonymous functions and it lets you skip the function keyword and write more concise code.
10. What are the different scopes in TypeScript?
The different scopes in TypeScript are:
Global Scope: Can be used anywhere in the program. Global Scope is defined outside of any class.
Local Scope/Code Block: These variables are defined in the local scope. They can be used anywhere in a block.
Function/Class Scope: These variables are defined in a function or class. They can be used anywhere within that scope.
11. How do you make all interface properties optional?
Partial mapped types can be used to easily make all properties optional.
12. How do you use TypeScript for the backend?
With Node.js, you can use TypeScript for backend work. Install the TypeScript compiler into Node.js with this command:
npm i -g typescript
Over to you!
There you have it! Now you know what the 12 top TypeScript interview questions are.
But interviews are only one part of your recruitment process. You also need to assess your candidates’ technical skills. How? With a skill assessment tool.
That’s what we offer at CodeSubmit. You can easily set up proven skill assessments that candidates complete online.
Want to learn more?