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October 30, 2023

TypeScript vs JavaScript: When To Use

Discover the key distinctions between TypeScript and JavaScript and enhance your coding skills with this informative article on their fundamental differences.

Kseniya Nestsiarovich

JavaScript Engineer

How is TypeScript different from JavaScript? Have you found yourself in the middle of that debate? Do you wonder how is TypeScript different from JavaScript? As JavaScript has become a ubiquitous language, so too has its typed superset, TypeScript. Both languages have their pros and cons, but when should you use either?

In this article, we will provide an overview of the differences between the two languages and discuss the best cases in which to use each one. So go ahead and learn more about TypeScript vs. JavaScript—and when you should use them.

What is TypeScript?

TypeScript is a typed superset of JavaScript that compiles to plain JavaScript. It adds syntax on top of the language to let engineers add the data types within the code to improve its ability to catch errors. When the code becomes huge, complex to handle, and prone to errors, it is better if the errors are caught during compile time itself. That is where TypeScript helps.

TypeScript programs typically consist of modules, functions, variables, comments, expressions, and statements—just like any other full-fledged programming language.

TypeScript can also be used with popular frameworks like React, Angular, and Vue, which provide additional benefits like pre-built components and optimized performance. While TypeScript has a learning curve, it can ultimately lead to more efficient and reliable code, making it a valuable tool in modern web development.

What is JavaScript?

JavaScript is a scripting language that is used to develop web applications. This is an interpreted, high-level language, with JIT (Just-in-Time) compiler and dynamic typing. For a long time, JavaScript was only a client-side implementation, but some newer engines also have server-side implementations. In addition, this technology is supported by all major browsers, allows you to create interactive and dynamic web applications and much more.

As of 2023, JavaScript is the most used programming language.

JavaScript stats
Source: Statista

Difference between TypeScript and JavaScript

What is the difference between TypeScript and JavaScript? Let’s briefly compare these two technologies before we delve into them deeper.

Superset of JavaScript developed to overcome code complexity for large projectsA scripting language that helps create dynamic web page content
Errors can be found and corrected during compile timeErrors can be found only during run-time as it is an interpreted language
Strongly typed, supports both static and dynamic typingWeakly typed, no option for static typing
Converted into JavaScript code to be understandable for browsersСan be directly used in browsers
Since it is a superset, all the JavaScript libraries and code work without changesLibraries work by default
Supports modules, generics, and interfaces to define dataNo support for modules, generics, or interface
Powerful and intuitive language for large projectsNeat and clean, most suitable for simple web applications
Community support is still growingHuge community support with lots of documentation and support for solving issues
Takes time to learn and code, scripting knowledge is a mustCan be learned on the go, no prior scripting experience is needed
Proper build setup (npm package) is required for static type definitionsNo build setup is required

Advantages and disadvantages of using TypeScript

Is TypeScript better than JavaScript? Well, it depends. This technology can offer you plenty of advantages, but you also should be aware of pitfalls you may face while working with it.


Advantages of TypeScript
  • Static typing: TypeScript introduces static typing to JavaScript, allowing developers to specify data types for variables, function parameters, and return values. This helps catch type-related errors at compile-time rather than runtime, making the code more robust and easier to maintain.

  • Enhanced IntelliSense: TypeScript provides improved code intelligence support in code editors and IDEs. With static typing, editors can offer better code completion, real-time error checking, and more helpful suggestions while you write code. This significantly enhances developer productivity.

  • Better tooling: TypeScript comes with a rich set of development tools that make it easier to manage and scale large codebases, improve code quality, and streamline development workflows.

  • Larger community: TypeScript has gained widespread adoption in the web development community. This large user base means there's a wealth of resources, libraries, and community-driven support available, making it easier to find solutions to common problems and get help when needed.

  • Interoperability with JavaScript: TypeScript is a strict superset of JavaScript, which means you can seamlessly incorporate existing JavaScript code into a TypeScript project. This makes it easier to transition to TypeScript gradually, as you don't have to rewrite your entire codebase.

  • Type safety: By providing strong typing and type inference, TypeScript helps prevent a wide range of common programming errors. This leads to more predictable code behavior, reducing the likelihood of runtime errors and making code easier to maintain.

  • Readability: TypeScript's static typing can enhance code readability. When you explicitly declare data types for variables and function signatures, it becomes easier for other engineers (and your future self) to understand the intent and usage of various parts of your codebase.

  • Scalability: TypeScript is particularly well-suited for large and complex projects. The type system helps in maintaining code quality and preventing regressions as the codebase grows. Additionally, tools like module systems and namespaces facilitate structuring code for scalability.

  • Performance: While TypeScript itself doesn't directly affect runtime performance, the early error detection and code optimization provided by the TypeScript compiler can lead to more efficient JavaScript output. Furthermore, TypeScript can leverage the latest ECMAScript features and optimizations.


Disadvantages of TypeScript
  • Learning curve: TypeScript introduces additional concepts and syntax compared to plain JavaScript, which can lead to a steeper learning curve for engineers who are new to the language.

  • Bloat: TypeScript can add some overhead to your codebase in terms of file size because of the type annotations and additional code required for type checking. However, this overhead is usually minimal compared to the benefits it provides in terms of maintainability and reduced runtime errors.

  • Not all features are supported: TypeScript is a superset of JavaScript, but not all JavaScript features are fully supported or easily type-checked. Some language constructs may require complex type definitions or workarounds, which can be cumbersome.

  • Not all IDEs support TypeScript: While TypeScript has strong support in popular code editors like Visual Studio Code, some other IDEs or text editors may not have as robust TypeScript integration. This can be a limitation for engineers who prefer different development environments.

  • TypeScript is not a silver bullet: TypeScript helps catch many types of errors at compile-time, but it doesn't eliminate all potential issues in your code. Engineers still need to write meaningful type annotations, design robust code, and handle runtime errors or edge cases.

  • TypeScript can be verbose: The type annotations and declarations in TypeScript can make the codebase more verbose compared to plain JavaScript. This verbosity can be seen as a disadvantage, particularly in smaller projects where the benefits of TypeScript may not be as pronounced.

  • TypeScript can be slow: The TypeScript compilation process, especially in large codebases, can be slower than plain JavaScript.

Advantages and disadvantages of using JavaScript

Moving on to JavaScript. This technology also has its own pros and cons, so you need to be aware of them to make informed decisions about your tech stack.


Advantages of JavaScript
  • Widely used: JavaScript is one of the most widely used programming languages in the world. It runs in web browsers, making it essential for web development. Additionally, it can be used on the server side (Node.js) in mobile app development (React Native) and desktop app development (Electron), making it a versatile choice.

  • Easy to learn: JavaScript is known for its relatively low entry barrier. It has a simple and approachable syntax that makes it accessible to beginners. It's often the first programming language that many developers learn.

  • Versatile: This language can be used for front-end web development to create interactive and dynamic user interfaces, as well as for back-end development, allowing for full-stack development. It can also be used for game development, IoT applications, and more.

  • Extensible: JavaScript can be extended through the use of libraries and frameworks. The extensive ecosystem of libraries and frameworks (e.g., React, Angular, Vue.js, Express.js) makes it easier to build complex applications without reinventing the wheel.

  • Fast: Modern JavaScript engines, such as V8 (used in Chrome) and SpiderMonkey (used in Firefox), are highly optimized and can executed very quickly. This enables the development of responsive and high-performance web applications.

  • Portable: The code can run on various platforms and devices, thanks to its cross-browser compatibility and the ability to run on server-side and other environments using tools like Node.js. This portability is valuable for reaching a wide audience.

  • Open source: JavaScript itself, along with many of its associated libraries and frameworks, is open source. This fosters a collaborative and community-driven development environment, allowing engineers to contribute to and benefit from a wealth of open-source projects.

  • Community: JavaScript has a vast and active developer community. This community contributes to its growth, provides support through forums, Q&A sites, and resources like tutorials and documentation, and continuously innovates with new tools and practices.


Disadvantages of JavaScript
  • Dynamic typing: Dynamic typing means that variables are not bound to specific data types. While this flexibility can be useful, it can also lead to unexpected behavior and runtime errors, especially in large and complex codebases.

  • Readability: JavaScript's permissiveness can lead to less readable code, particularly when engineers don't follow consistent coding conventions. This can make it harder to understand and maintain code over time.

  • Scalability: This language can be challenging to scale for very large projects. Without strong typing and stricter organizational practices, it can become difficult to manage and maintain as a codebase grows.

  • Performance: While the engines have improved significantly over the years, JavaScript may still not be as performant as other languages for certain compute-intensive tasks. It's important to consider performance bottlenecks when using JavaScript for specific applications.

  • Security: JavaScript running in a browser has certain security limitations. It can be vulnerable to cross-site scripting (XSS) attacks if not handled properly. Developers need to be vigilant about security practices to protect against potential vulnerabilities.

  • Interoperability: It may not always integrate seamlessly with other programming languages or systems, especially in scenarios where you need to interface with legacy or non-browser environments.

  • Tool support: While JavaScript has a rich ecosystem of development tools and libraries, the tooling landscape can be fragmented. Different tools and frameworks may have varying levels of support, and it can be challenging to choose the right tools for a particular project.

  • Learning curve: While JavaScript itself is relatively easy to learn, mastering it for complex applications can be challenging. As projects become more sophisticated, engineers need to learn advanced concepts and best practices.

  • Bloat: JavaScript codebases can become bloated due to the inclusion of unnecessary libraries, dependencies, or features. This can impact performance and load times.

  • Fragmentation: The JavaScript ecosystem is known for its fragmentation. There are numerous libraries, frameworks, and build tools to choose from, which can lead to decision fatigue and difficulty in maintaining consistency across projects.

Why choose Yellow for TypeScript and JavaScript development

Choosing Yellow can be a game-changer for your project. Our development team comprises seasoned TypeScript and JavaScript engineers who are well-versed in the latest trends, tools, and frameworks. They bring deep technical knowledge to the table.

Advantages and Disadvantages of React.js: The Detailed Overview

There are lots of reasons to appreciate React — be it its declarative nature or shared libraries of ready-to-use components. Still, there may be some negative points to take into account. Here is the list of pros and cons of React.

Learn more

We prioritize efficiency in coding and development practices, ensuring faster turnaround times without compromising quality. Our streamlined workflows and well-established best practices save you time and resources.

By choosing our TypeScript and JavaScript development agency, you gain a competitive edge with top-tier expertise, efficiency, customized solutions, and dependable support for your software needs.

TypeScript vs JavaScript: Conclusion

The final thoughts on the TypeScript versus JavaScript dispute. TypeScript is not a replacement for JavaScript, but it is a great language that will help you create large-scale applications more efficiently. Even though it has a few drawbacks, such as increased compilation time, it will save you time in the long run. In its turn, JavaScript is an old and proven web development technology with a complete online source of educational materials.

There is no need to limit yourself to one of them when it comes to TypeScript or JavaScript. There are not as many differences between TypeScript and JavaScript as you might think, but these differences can be significant.

🖥️ Can I use JavaScript code in TypeScript?

Yes, you can use JavaScript code in TypeScript seamlessly, as TypeScript is a superset of JavaScript. TypeScript simply adds static typing and additional features.

🖥️ Can I use TypeScript code in JavaScript?

Yes, but TypeScript-specific features, such as type annotations and interfaces, will not be recognized or enforced by JavaScript interpreters or compilers.

🖥️ Is TypeScript easier than JavaScript?

Some engineers find TypeScript easier because it provides strong type checking, which can catch errors early, while others may find JavaScript simpler due to its dynamic typing and fewer language features to learn.

🖥️ Is TypeScript performance better than that of JavaScript?

TypeScript does not inherently offer better performance. Performance depends on factors like code quality, runtime optimizations, and the specific use case.

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