Most popular TypeScript interview questions and answers

If you are looking for TypeScript developer interview questions, go through this curated list of TypeScript interview questions and answers for acing that interview.

Last updated on Mar 21, 2023

TypeScript is a typed JavaScript superset that translates to plain JavaScript. TypeScript is essentially the ES6 version of JavaScript with some added capabilities. It is entirely object-oriented, with classes, interfaces, and programming languages that are statically typed, such as C# or Java. To build and produce the code in a JavaScript file, you will need a compiler.

Whether you are a candidate actively looking for TypeScript developer jobs or a recruiter looking for TypeScript developers, the following list of TypeScript interview questions will be of great use to you.

TypeScript interview questions and answers


What are the Advantages of TypeScript?

The following are the advantages of using TypeScript:

  • TypeScript is a fast, straightforward, and easy-to-learn scripting language that can be run on any browser or JavaScript engine.
  • It is comparable to JavaScript in that it employs the same syntax and semantics.
  • This allows backend developers to write front-end code more quickly.
  • The TypeScript code can be called from existing JavaScript code. It also works flawlessly with existing JavaScript frameworks and libraries.
  • The Definition file, with the.d.ts extension, supports existing JavaScript libraries such as Jquery, D3.js, and others.


What are the various types of TypeScript?

The TypeScript programming language supports different types of values. It provides data types for JavaScript, allowing it to be transformed into a strongly typed programming language. Although JavaScript does not support data types, we can use the data types functionality in JavaScript with the help of TypeScript. When an object-oriented programmer wishes to use the type feature in any scripting language or object-oriented programming language, TypeScript comes in handy. Before the program uses the specified values, the Type System validates them. It guarantees that the code behaves correctly. It validates the provided values before they are saved or changed by the program. It is divided into two categories, which are as follows:

  • Number, String, boolean, void, null, and undefined are examples of built-in values.
  • User-defined: Enumerations (enums), classes, interfaces, arrays, and tuples are all part of it.


What are the TypeScript components?

TypeScript has three different sorts of components, which are as follows:

  • Language is made up of syntax, keywords, and type annotations.
  • TypeScript Compiler (tsc) This compiler (tsc) transforms TypeScript instructions to JavaScript equivalents.
  • The TypeScript Language Service is a service that allows you to write code in TypeScript. The language service supports the standard set of editor operations. The Language Service presents an additional layer, editor-like applications, around the basic compiler pipeline.


Who is TypeScript’s developer?

Anders Hejlsberg created TypeScript. In addition, he is a key part of the C# language development team. The TypeScript was first released on October 1st, 2012, with the version number 0.8. However, Microsoft developed and maintains it under the Apache 2 license. It was intended for the creation of a huge application.


Is it possible to integrate multiple.ts files into a single.js file?

Yes, numerous files can be combined. We must include the –outFILE [OutputJSFileName] option when compiling.


What access modifiers does TypeScript support?

TypeScript supports the access modifiers public, private, and protected, which determine a class member's accessibility, as shown below:

Public - All members of the class, its child classes, and the class instance have access to it.

Protected - All members of the class and its subclasses have access to them. However, the class instance is unable to access.

Private - Only class members have access to these.

If no access modifier is supplied, it is assumed to be public due to the handy nature of JavaScript.


What are variables in TypeScript?

A variable is a named memory region that is used to store values. In TypeScript, the type syntax for declaring a variable comprises a colon (:) after the variable name, followed by its type.


What is the difference between TypeScript and a statically typed language?

TypeScript is optionally statically typed, which means you can tell the compiler to ignore a variable's type. We can assign any type of value to the variable using any data type. During compilation, TypeScript will not perform any error checking.


What are TypeScript Interfaces?

For type-checking, the TypeScript compiler employs an interface that determines whether or not an object has a specified structure. The interface is a structure in your program that defines the contract. It specifies the syntax that classes must use. It just declares the members; it is the job of the derived class to define the members.


What exactly are Mixins?

  • Mixins in Javascript are a method of constructing classes from reusable components and then constructing them by merging simpler partial classes.
  • Instead of class A extending class B to obtain its functionality, function B accepts class A and produces a new class with this extra capability. Function B is a mixin.

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Wrapping up

The above list of TypeScript interview questions will be an important part of your TypeScript interview preparation. These TypeScript interview questions will assist you in solving similar queries or generating new ones. A TypeScript interview, on the other hand, would not consist solely of these technical TypeScript interview questions. A TypeScript interview may also include questions regarding a person's social and life abilities. This allows the recruiter to determine whether the individual can persevere in difficult situations while also assisting their coworkers. As a recruiter, finding someone who gets along with the rest of the team is critical.

You can work with Turing if you're a recruiter looking to hire from the top 1% of TypeScript developers. If you're an experienced TypeScript developer searching for a new opportunity, is a great place to start.

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