TypeScript interview questions are typically asked in technical rounds of software engineering interviews. If you specifically prefer coding in JavaScript or TypeScript, it is important to know answers to TypeScript interview questions around the language’s core features, classes, methods, types, and functionalities.

TypeScript is a superset of JavaScript and is a programming language in itself. It is mainly used to build large-scale programs and enterprise applications. If you're a JavaScript developer, you can expect TypeScript interview questions at technical screens and online assessments of developer interviews.

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Let’s look at some popular TypeScript interview questions asked in technical interviews. To better understand what type of questions to expect, we’ll look at TypeScript interview questions for freshers and experienced professionals.

Here’s what we’ll cover in this article:

• TypeScript Interview Questions and Answers for Freshers
• TypeScript Interview Questions for Experienced Programmers
• TypeScript Coding Interview Questions
• FAQs on TypeScript Interview Questions

TypeScript Interview Questions and Answers for Freshers

As a fresher, you can expect TypeScript interview questions at Java and JavaScript developer interviews. Let’s go ahead and look at some common TypeScript interview questions and answers for freshers.

Q1. What do you understand about arrays in TypeScript?

Arrays in TypeScript are a collection of items of the same data type. The elements in an array are indexed and ordered.

Q2. What are some common applications and benefits of TypeScript?

This is one of the most common TypeScript interview questions asked in technical interviews. Some common applications and benefits of using TypeScript include:

• It can be used to write and build both client-side and server-side applications
• It can be used to create enterprise applications
• It can be used as a substitute for JavaScript as it is a superset of JavaScript
• It allows developers to use 3rd party libraries
• It suggests code errors to help developers make immediate changes to the source code whenever required, avoiding post-production errors.

Q3. Can you erase the values of array elements in TypeScript?

No, the values of array elements can only be modified but not erased in TypeScript.

Q4. Which are the different access specifiers supported by TypeScript?

The three access specifiers supported by TypeScript include:

• Private - only members within the class have access
• Public - members inside and outside the class have access
• Protected - only child classes and members within the class have access

Q5. How do you convert a given string into a number in TypeScript? What methods can you use?

This is another important TypeScript interview question that is asked at technical interviews. To convert a string into a number, the methods you can use include:

• ParseInt()
• ParseFloat()
• Number()

Sample TypeScript Interview Questions for Your Tech Interview

Let’s look at some sample TypeScript interview questions to help you prepare for your upcoming tech interview.

1. What are primitive data types in TypeScript?
2. What do you understand about the void data type in TypeScript?
3. Which keywords are used to declare TypeScript variables?
4. How do you specify Optional Properties in TypeScript?
5. What do you understand about the “never” type in TypeScript?
6. How do Enums work in TypeScript?
7. What do you understand about the Typeof operator in TypeScript?
8. Explain parameter destructuring in TypeScript.
9. What is the syntax to create Classes in TypeScript?
10. What is the use of the arrow function in TypeScript?

TypeScript Interview Questions for Experienced Developers

Advanced TypeScript interview questions are often asked at interviews for experienced developers. To give you an idea of the type of questions asked, let’s look at some TypeScript interview questions for experienced developers.

Q1. What is the function of the Omit type in TypeScript?

This is one of the most common TypeScript interview questions asked at developer interviews. The Omit type is primarily used to exclude certain properties from a class.

Q2. What are some disadvantages associated with TypeScript?

Some disadvantages of using TypeScript include:

• TypeScript as a language does not support abstract classes
• TypeScript takes a long time to compile code
• Definition files are necessary while using 3rd party libraries in TypeScript

Q3. What does the Record type in TypeScript do?

The Record type in TypeScript helps you create a typed map, allowing you to perform various functions, including defining map tiles and translating coordinate systems to scale.

Q4. What is the function of the .map file in TypeScript?

The .map file in TypeScript is used for debugging code. The .map can be used by setting the sourcemap compiler option as true in the tsconfig.json.

Q5. What are some drawbacks of using TypeScript declaration files?

This is one of the most popular TypeScript interview questions asked at developer interviews. Some drawbacks of using TypeScript declaration files are:

• When you upgrade the TypeScript version, you’re required to change the declaration files as DOM APIs change often, making it difficult to carry out the process manually.
• It is difficult to customize declaration files in TypeScript.

Sample TypeScript Interview Questions for Experienced Programmers

If you’re an experienced developer who codes in TypeScript or JavaScript, below are some sample TypeScript interview questions that you can expect at your interview.

1. How do you go about compiling TypeScript with Visual Studio Code?
2. Explain the Awaited type in TypeScript
3. What do you understand about Recursive Type Aliases
4. Explain the different components of TypeScript with examples
5. Explain conditional data types in TypeScript.
6. What are modules in TypeSCript? Explain with an example.
7. What do you understand about Rest Parameters in TypeScript?
8. What are decorators in TypeScript?
9. Explain the Lambda function in TypeScript
10. Explain how TypeScript can be used for backend development

TypeScript Coding Interview Questions

Software engineering interviews typically involve solving coding problems in the preferred language. If you’re a TypeScript or JavaScript developer, you can use TypeScript/JavaScript to solve core data structures and algorithms problems that feature in technical interviews.

We’ve listed some TypeScript programming interview questions that feature in tech interviews to give you a clear idea.

1. Write a program to find the missing element in an array using TypeScript
2. Write a program to implement Breadth-First Search and Depth First Search using TypeScript
3. Write a code to determine if a string is a palindrome or not
4. Write a program to convert a binary tree to a doubly-linked list
5. Write a program to implement and illustrate the binary search algorithm without using Recursion

For more coding problems, check out our all-inclusive Problems Page.

Make sure to practice these above TypeScript interview questions to get ready for your next interview!

FAQs on TypeScript Interview Questions

Q1. What is TypeScript?

TypeScript is a programming language used to build large-scale enterprise and software applications. It is a superset of JavaScript and allows for static typing.

Q2. What are some advantages of using TypeScript?

Some advantages of using TypeScript include - i) it is easy to learn and has the same syntax as JavaScript ii)it allows developers to write code faster through suggestions iii) TypeScript can be called from JavaScript code iv) it allows integration of 3rd party libraries.

Q3. What type of TypeScript interview questions are asked at software engineering interviews?

TypeScript interview questions asked at software developer interviews are mostly around data types, functions, methods, directives, libraries, and types.

Q4. What are some important topics to prepare to answer TypeScript coding interview questions?

Some important topics to prepare to solve TypeScript coding interview questions effectively are - Linked Lists, Arrays, Graphs, Trees, Greedy Algorithms, Recursion, and Hash Tables.

Q5. What is the average TypeScript developer salary in the US?

The average TypeScript developer salary in the US is $80,760 per year, according to glassdoor.com

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