Difference between TypeScript and JavaScript

Both TypeScript and JavaScript are used at the client-end for processing the server requests and rendering data on UI. Both are scripting languages, however Typescript supports some additional features, due to which it is sometimes regarded as the superset of JavaScript. Read through this article to find out more about TypeScript and JavaScript and how these two languages are different from each other.

What is JavaScript?

JavaScript is most often used as a component of webpages. Its webpage implementations enable client-side script to interact with the user and create dynamic sites. It is a programming language that is interpreted and can handle object-oriented functionality.

One of the most significant advantages of JavaScript is that it does not call for the use of pricey development tools. You may get started with something simple like Notepad as your text editor. Because it is a language that is interpreted inside the environment of a web browser, you won't even need to acquire a compiler to use it.

Characteristics of JavaScript

Following are some of the characteristic features of JavaScript −

  • JavaScript is supported by all popular web browsers because they have a built-in environment for running it.

  • The syntax and structure of the computer language C are adopted wholesale by JavaScript. Therefore, we may classify it as a "structured programming language."

  • JavaScript is a weakly typed programming language, which means that some types are cast automatically (depending on the operation).

  • In JavaScript, inheritance is handled through the use of prototypes instead of classes.

  • JavaScript works on a wide range of operating systems such as Windows, macOS, and others.

Creating interactive webpages often requires the usage of JavaScript. Its primary applications include client-side validation, creating dynamic drop-down menus, including date and time features, putting up new windows and dialogue boxes as they appear (like an alert dialogue box, confirm dialogue box, and prompt dialogue box), etc.


Take a look at the following sample code −

<script type="text/javascript"> document.write("Hello World"); </script>

What is TypeScript?

TypeScript is a strongly typed, object oriented, compiled language. It can be thought of as a superset of JavaScript. TypeScript was developed and promoted in order to overcome some of the issues related to JavaScript, such as its inability to handle all the concepts of object orientation, absence of strong type checking and compile-time error checking.

Features of TypeScript

Here are some of the prominent features of TypeScript −

  • The TypeScript compiler converts the instructions written in TypeScript to its JavaScript equivalent.

  • TypeScript adopts the basic building blocks of JavaScript. It supports all other JS libraries. Hence, all that you need to know is JavaScript in order to use TypeScript.

  • TypeScript-generated JavaScript can reuse all the existing JavaScript frameworks, tools, and libraries. A valid ".js" file can be renamed to ".ts" and compiled with other TypeScript files.

  • TypeScript is portable across browsers, devices, and operating systems. It can run on any environment that JavaScript runs on.

  • JavaScript is an interpreted language, whereas TypeScript will compile the code and generate compilation errors, if it finds some sort of syntax errors.

  • TypeScript supports Object Oriented Programming concepts like classes, interfaces, inheritance, etc.


Take a look at the following TypeScript code −

var hello: string = "Hello"; var world: string = "World"; console.log(hello + " from " + world);

It will produce the following output −

Hello from World

Difference between TypeScript and JavaScript

The following table highlights the major differences between TypeScript and JavaScript −

Key TypeScript JavaScript
Type Typescript is a strongly typed object-oriented compiled language. It was developed by Microsoft. JavaScript is a lightweight interpreted language. It was introduced by Netscape.
Internal implementation Internal implementation of Typescript does not allow it to be used at the server side. It can only be used at the client side. JavaScript can be used both at the client side and the server side.
Data binding For binding the data at code level, Typescript uses concepts like types and interfaces to describe data being used. No such concept has been introduced in JavaScript.
Compilation Code written in TypeScript first needs to get compiled and then converted to JavaScript. This process of conversion is known as Transpilation. No compilation is needed in case of JavaScript.
Modular programming TypeScript supports modules, hence it allows modular programming. JavaScript does not support modules and hence it does not allow modular programming.
Optional parameter in function Any number of optional parameters are allowed in function code written in Typescript. JavaScript does not support optional parameter function.


The most important point that you should note here is that TypeScript was developed to overcome the limitations of JavaScript. TypeScript is strongly typed, object-oriented, and compiled, whereas JavaScript is lightweight and interpreted. TypeScript is regarded as a superset of JavaScript.