TypeScript vs JavaScript

TypeScript and JavaScript are two complementary languages guiding frontend and backend development. In this article, we will explore the main differences among them and the context in which each language is better suited.

 

What is JavaScript?

JavaScript is a programming language created in 1995 by Brendan Eich, an American programmer also known for being Mozilla's cofounder. The scripting language was initially called LiveScript and was created for the Netscape Navigator, Netscape Communications' top browser. Since the release of its first standard in 1997, JavaScript has come a long way, so much so that if we compare the first standard with its last release (ECMAScript 2023 or ES14), they appear to be two different languages.

JavaScript continues to be the most used scripting language, as confirmed by the most recent Stack Overflow 2024 survey: 64% of professional developers declare to use it. This is partly also due to the prominence of frontend frameworks like React, Angular and Vue.js.

It is a scripting language that works on the principles of client-side programming, so it runs directly in the user's browser without requiring resources from the server. It can be integrated with other technologies, such as REST APIs, XML and others.

 

What is TypeScript?

TypeScript was created in 2010 by Anders Hejlsberg (a Danish software engineer, known also for his role as chief architect for C#) for Microsoft and released to the public in 2012. The purpose was to facilitate the development of big and complex applications, and the language's popularity is highly increasing. It is used by more than 44% of respondents, according to the latest Stack Overflow 2024 survey on the most appreciated languages.

The language is a modern version of JavaScript. It has a static with static compilation conceived to generate clean and readable JavaScript code. It can be executed on Node.js and on every browser compatible from ECMAScript 3 onwards.

TypeScript introduces optional static typing, along with classes and interfaces. In large-scale JavaScript projects, the adoption of TypeScript can make software more stable and easier to deploy than an application developed solely with JavaScript.

 

Differences between JavaScript and TypeScript

Up to this point, the two languages may appear similar, but there are a number of differences:

Type system

JavaScript is a dynamic programming language, i.e., the types of variables are determined at runtime. TypeScript, on the other hand, is static and, consequently, requires programmers to define variable types when writing code.

Compilation

JavaScript can be executed directly in the browser or in an environment such as Node.js without requiring a compilation step. TypeScript, on the other hand, must be compiled into JavaScript before it can be executed.

Optional parameters

JavaScript does not directly support optional parameters, which must therefore be handled manually. In TypeScript, optional parameters are integrated directly into the language.

Null handling

JavaScript manages null and undefined values fairly permissively, allowing comparisons and operations even on undefined values. TypeScript has stricter support for null and undefined values, including null type annotations and null checking.

Object-oriented features

TypeScript provides better support for object-oriented programming features such as classes, interfaces, and inheritance. JavaScript supports object-oriented programming through a prototype-based system.

Enums

TypeScript supports enums, which make it easy to create and manipulate sets of related data. JavaScript, on the other hand, does not support them natively, forcing programmers to simulate this functionality with objects or arrays.

Type checking

TypeScript has a built-in type-checking system that helps detect errors at compile time. Type checking in JavaScript only occurs at runtime.

Support tools

TypeScript has better support for tools, including IDE plugins and code editors. This is because while enjoying broad support from development tools, JavaScript has dynamic typing that can make auto-completion and error detection less accurate.

Code compatibility

TypeScript is backward compatible with JavaScript. It can execute any JS, but the latter cannot execute TS.

Code maintainability

TypeScript offers better maintainability and scalability of code due to type annotations and better support for OOPs. The maintainability of JavaScript code can be problematic in large projects.

 

When to use JavaScript vs TypeScript

Choosing between JavaScript and TypeScript mainly requires thinking about the needs of the project and the context of use.

JavaScript lends itself well to smaller and lighter projects, where the focus is on speed of development and ease of integration. It is often the most appropriate choice for simple websites or applications that do not require complex code management. The learning curve of JavaScript, which is lower than that of TypeScript, must be taken into consideration.

TypeScript, on the other hand, is perfect for large projects and complex, scalable applications, where maintainability and code robustness play a key role. Its static typing helps prevent errors during development and offers better readability and organisation of the code, especially in large teams. Compared to JavaScript, however, the learning curve is higher. 

 

Conclusion

As we have seen, the choice between TypeScript and JavaScript depends on the specific needs of each project. JavaScript offers simplicity and flexibility, making it perfect for small-scale projects or for novice developers. On the other hand, TypeScript, with its static type system and support for object-oriented programming, is particularly useful for handling large and complex projects.