TypeScript Tutorial

TypeScript lets you write JavaScript the way you really want to. TypeScript is a typed superset of JavaScript that compiles to plain JavaScript. TypeScript is pure object oriented with classes, interfaces and statically typed like C# or Java. The popular JavaScript framework Angular 2.0 is written in TypeScript. Mastering TypeScript can help programmers to write object-oriented programs and have them compiled to JavaScript, both on server side and client side.

This TypeScript tutorial has been designed for beginners as well as working professional to help them understand the basic to advance concepts of TypeScript. It covers most of the important concepts related to TypeScript such as type system, control flow, functions, interfaces, classes and objects, advanced types, type manipulation, generics, namespace, modules, decorators and many more.

Why to Learn TypeScript?

TypeScript is a popular choice for developing web applications. It is also used in other areas such as game development and server-side development. TypeScript is a free and open-source high-level programming language. It’s very easy to learn if you are already familiar with JavaScript. You need to understand the type system and related syntax to apply them to JavaScript code. By mastering TypeScript, you”ll be well-positioned for a variety of software development roles.

In addition to the above, here are some more reasons to learn the TypeScript programming language:

• It adds static typing with optional type annotations to JavaScript.

• TypeScript is designed for the development of large applications.

• It helps developers catch errors early in their code editor.

• It supports all the latest ECMAScript features.

• TypeScript is the recommended language for creating apps with the Angular framework.

• It can also be used for game development and server-side development.

• All the big companies such as Microsoft, Google, Meta, Amazon, etc., use TypeScript.

• TypeScript supports JavaScript libraries. You can easily use JavaScript libraries in your TypeScript projects.

• A huge community of TypeScript is available on the internet and growing rapidly. Anyone can easily get support.

• There are tons of jobs available for those who know TypeScript.

Applications of TypeScript

TypeScript is a versatile programming language that can be applied across a wide range of applications.

• Web development: TypeScript is extensively used in building dynamic and interactive web applications. The popular framework Angular is entirely built on TypeScript, and other JavaScript frameworks such as React and Vue.js support TypeScript. TypeScript enables developers to create robust web applications with enhanced type safety and better tooling support.

• Server-side development: TypeScript is increasingly used with server-side development with Node.js. Frameworks like NestJS use TypeScript to build server-side applications.

• Mobile development: With TypeScript, you can develop cross-platform mobile applications using frameworks like React Native.

• Desktop app development: TypeScript can also be used to develop desktop applications through frameworks like Electron.

• Game development: TypeScript is used in game development, particularly for web-based games.

• Large-scale development: TypeScript is well suited for large-scale applications. Its static typing, interfaces, and modularization capabilities help keep the codebase organized and scalable.

• Library and framework development: You can develop your own library or framework using TypeScript. Many popular frameworks are written in TypeScript.

Who Should Learn TypeScript?

Programmers coming from the Object-Oriented world will find it easy to use TypeScript. With the knowledge of TypeScript, they can build web applications much faster, as TypeScript has good tooling support.

Prerequisites to Learn TypeScript

As a reader of this tutorial, you should have a good understanding of OOP concepts and basic JavaScript to make the most of this tutorial.

TypeScript Jobs

The demand for TypeScript developers has been steadily increasing as more companies adopt it for their projects. Here are some of the most popular companies that offer the role of TypeScript developer:

• Microsoft
• Google
• Meta
• Amazon
• Netflix
• Airbnb
• Many more…

TypeScript Career Opportunities

There are several career paths that you can choose after learning TypeScript. Here, we have listed some of them:

• Web developer
• Front-end developer
• Back-end developer
• Full-stack developer
• Game developer
• Mobile developer
• DevOps Engineer
• Many other roles

Libraries and Frameworks

Many popular frameworks and libraries are either entirely written in TypeScript or support TypeScript. Some of the popular frameworks/libraries are as follows:

• Angular: It is developed entirely with TypeScript.

• React: It supports TypeScript through DefinitelyTyped type definitions and official support.

• Vue.js: It provides TypeScript support via the Vue CLI.

• NestJS: It is a progressive Node.js framework built with TypeScript for building efficient and scalable server-side applications.

Compile/Execute TypeScript Programs

We have provided Typescript Online Compiler which helps you to Edit and Execute the code directly from your browser. Try to click the icon to run the following Typescript code to print conventional “Hello, World!”.

Try to change the value of string variable and run it again to verify the result.

var message:string = "Hello World" 
console.log(message)

On compiling, it will generate following JavaScript code.

var message = "Hello World";
console.log(message);

Frequently Asked Questions About TypeScript

There are some very Frequently Asked Questions(FAQ) about TypeScript, this section tries to answer them briefly.

What is Typescript, and how does it differ from JavaScript?

TypeScript is an open-source programming language that is an extended version of JavaScript. It is statically typed and built on top of the existing syntax and functionalities in JavaScript. Typescript can be integrated easily with the JavaScript eco-system and modern frameworks like React and Angular, making it reliable for creating and managing large-scale web-applications.

Typescript”s advanced features include classes, interfaces and generics which facilitate the design of modular code for complex web applications. The typed annotations and extended OOP features aid in understanding, debugging and maintaining code. Additionally, Typescript executes strict null checks, unlike JavaScript, which helps to identify null or undefined values during compilation, hence reducing the runtime errors.

Why should I use TypeScript?

TypeScript provides several benefits, including:

• Type Safety: Helps catch errors early through static type checking.

• Enhanced Tooling: Offers better code editors” support with features like autocompletion, navigation, and refactoring.

• Improved Code Quality: Enforces coding standards and best practices.

• Better Collaboration: Makes code more readable and easier to maintain, especially in large teams and projects.

• Compatibility: Compiles to plain JavaScript, ensuring compatibility with existing JavaScript libraries and frameworks.

How do I install TypeScript?

You can install TypeScript globally on your machine using npm (Node Package Manager). Run the following command in your terminal:

npm install -g typescript

What is tsconfig.json?

The tsconfig.json is a configuration file for TypeScript projects. It specifies the root files and the compiler options required to compile the project. Here is a basic example of a tsconfig.json file:

{
  "compilerOptions": {
    "target": "es6",
    "module": "commonjs",
    "strict": true,
    "esModuleInterop": true
  },
  "include": ["src/**/*"]
}

Can I use existing JavaScript libraries in TypeScript?

Yes, you can use existing JavaScript libraries in TypeScript. To do this, you may need type definitions for those libraries, which provide type information about the library”s functions and objects.

What are TypeScript interfaces?

Interfaces in TypeScript are used to define the shape of an object. They can be used to define types for objects, function parameters, and function return values. Here is an example –

interface Person {
  name: string;
  age: number;
}

function greet(person: Person): void {
  console.log(`Hello, ${person.name}`);
}

Can TypeScript be used for back-end development?

Yes, TypeScript is increasingly used for back-end development. Frameworks like Node.js and NestJS use TypeScript to build scalable and maintainable server-side applications.

How do I handle errors in TypeScript?

TypeScript helps prevent errors by catching them at compile time. However, you can still use traditional error handling techniques like try/catch blocks.

TypeScript Articles

You can explore a set of TypeScript articles at TypeScript Articles.