TypeScript vs. JavaScript: Differences & Which to Use

Despite both having “Script” in their names, there are differences between JavaScript and TypeScript that, as a coder, you should know about. Learning which one to use for your project can make your life easier and help optimize your project. 

Let’s dive into the similarities and differences between TypeScript and JavaScript, including which works best in which scenarios.

TypeScript vs. JavaScript: A Brief Overview

Before we can help you assess the differences between TypeScript and JavaScript, you need to understand what each of them does.

What is JavaScript?

JavaScript is a programming language that enhances websites by making them more interactive and dynamic. In back-end development, it works to add functionality, and in front-end development, it optimizes user experience (UX). With JavaScript, you can create things like responsive menus, image sliders, and form validations. JavaScript is popular among programmers because all modern web browsers support it, and it can be integrated with HTML and CSS to create powerful web applications.

What is TypeScript?

TypeScript is a programming language that builds on JavaScript. It adds more structure and organization to your code, making it easier to write and maintain. TypeScript also helps catch errors before running your code (something JavaScript can’t do, which we’ll discuss later). 

It provides tools for developers to work collaboratively, improves code readability, and enables better code documentation. TypeScript compiles into regular JavaScript, so it can be used on any platform that supports JavaScript. It's a popular choice for larger projects and teams, bringing additional reliability and scalability to JavaScript development.

Differences Between TypeScript and JavaScript

If TypeScript and JavaScript are so similar, what are the differences – and why do they matter?

Static vs. Dynamic Typing

Static typing and dynamic typing are approaches used in programming languages to handle what’s called “variable types,” or the different kinds of data that can be stored in a variable. 

JavaScript has dynamic typing, meaning you can assign different values to a variable without explicitly declaring its type. This flexibility allows for quick prototyping but can lead to runtime errors if unexpected types are used. For example, you can start with a variable "age" that stores a number like 25, but later in the code, you can assign a string like "thirty" to the same variable. JavaScript allows this flexibility of changing the type of a variable on the fly, which can be both convenient and potentially lead to unexpected results.

TypeScript, on the other hand, introduces static typing, which requires variables to be declared with specific types. It helps catch errors during development, improves code documentation, and enables better tooling support. However, static typing requires more upfront effort and can be seen as more restrictive for smaller projects or quick scripting tasks. Going back to the example above, you can declare a variable called "age" as a number, and TypeScript will enforce that it can only store numeric values. If you try to assign any other type to "age," TypeScript will show an error during development, helping you catch mistakes early and write more reliable code. 

Static vs. dynamic typing play important roles in many other aspects of TypeScript vs. JavaScript, as you’ll see below.

Object-Oriented Programming (OOP) Support

Object-Oriented Programming (OOP) is a programming paradigm that organizes code around objects that contain data and behavior. It promotes modularity (breaking down a big problem into smaller, manageable parts that can be solved independently), reusability, and easier code maintenance. 

TypeScript and JavaScript both support OOP, but TypeScript provides more robust support due to its static typing. In TypeScript, you can define classes (which are blueprints that define how objects should be created and what they can do), interfaces (contracts that define what methods and properties an object should have), inheritance (when a new class can inherit or get characteristics from an existing class), and access modifiers (words that control the visibility or accessibility of variables and methods within a class) to create robust and predictable object-oriented structures. 

OOP in TypeScript is beneficial for larger projects where code organization and scalability are crucial. It helps create modular and maintainable codebases, promotes code reuse, and enables better collaboration among developers working on the same project.

Type Inference

Another difference between TypeScript and JavaScript is in their approach to type inference. Type inference refers to the language's ability to automatically determine the type of a variable based on its assigned value. This means you don't have to explicitly declare the type every time. It improves developer productivity by reducing the amount of repetitive type annotations. 

TypeScript's type inference offers quicker development, cleaner code, and improved readability. It's especially useful when working on smaller projects or writing shorter code snippets where explicit type declarations may not be necessary, allowing developers to focus on writing code rather than specifying types.

Because of JavaScript’s dynamic typing (see above), it infers types at runtime rather than while writing, which means it may be harder to catch errors before runtime, thus lengthening the time a project takes.

Scalability

In the context of coding, scalability refers to the ability of a codebase to handle increasing complexity and size without becoming unmanageable. 

JavaScript is great for small projects and can handle moderate growth, but it can become harder to manage as projects get larger and more complex. An advantage is that JavaScript allows quick prototyping and flexibility. However, a disadvantage is that the code can become messy and harder to maintain without careful organization.

TypeScript offers more advantages for scalable projects than JavaScript because its static typing allows developers to catch errors early, ensure code consistency, and provide better tooling support (see below) for refactoring and maintaining large codebases. It enforces stricter rules and provides type checks, making it easier to scale a project as it grows. TypeScript's additional features, like interfaces and classes, contribute to code organization and modular development, making it a preferred choice for scalable applications.

Tooling

Tooling refers to the software tools and utilities that help developers write, debug, and manage their code effectively. 

JavaScript has a variety of tools to help developers write and manage code efficiently. Many code editors and linters (tools that help identify and highlight potential errors, style violations, and programming best practices) are available, making coding easier and catching errors. However, JavaScript lacks a built-in tooling ecosystem, so developers must choose and configure tools themselves. This can be overwhelming for beginners, but for experienced developers, it offers flexibility for their workflow.

TypeScript has more robust tooling support compared to JavaScript. TypeScript's tooling includes powerful code editors like Visual Studio Code, which offers features like intelligent code completion, error highlighting, and refactoring support (having tools that help modify and improve code without changing its behavior). Additionally, TypeScript has a dedicated compiler that checks for errors and generates JavaScript code.

Performance

TypeScript and JavaScript have similar performance characteristics since TypeScript ultimately compiles to JavaScript. Performance depends on various factors, including code efficiency, algorithms used, and runtime environments. 

Both languages can be optimized for performance by following best practices such as minimizing unnecessary computations, optimizing loops, and reducing memory usage. Performance testing is crucial to identify bottlenecks and optimize code. Tools like Chrome DevTools and profiling libraries can help analyze and improve performance in both TypeScript and JavaScript. 

It's important to note that while TypeScript offers static typing, which can catch certain errors and improve code optimization, it doesn't inherently provide a significant performance advantage over JavaScript.

Use Cases for TypeScript

TypeScript, as an enhanced version of JavaScript, has several practical use cases. Here are a few of the more popular uses for TypeScript.

Large-Scale Web Development

TypeScript is beneficial for building large and complex web applications. Its static typing helps catch errors early in the development process, making the code more reliable and maintainable as the project grows.

Codebase Collaboration

TypeScript's static typing allows multiple developers to work on the same codebase more efficiently. The clear type annotations and interfaces make it easier to understand and collaborate on different parts of the code.

Frameworks and Libraries

TypeScript is widely used in frameworks and libraries like Angular, React, and Vue.js. It enhances their capabilities by providing type checking, code auto-completion, and better tooling support, enabling developers to build the robust and scalable applications TypeScript is known for.

API Development

TypeScript is valuable for creating Application Programming Interfaces (APIs), which are sets of rules and protocols that allow different software applications to communicate and interact with each other, as well as back-end services. It brings type safety and better code organization to the server-side code, resulting in more maintainable and error-free APIs.

Cross-Platform Development

TypeScript can be used for developing cross-platform mobile applications using frameworks like Ionic and NativeScript. It allows code sharing between different platforms and ensures consistent behavior and type safety across iOS, Android, and web applications.

Use Cases for JavaScript

JavaScript is a versatile programming language with several practical use cases. Here are some examples.

Website Interactivity

JavaScript is among the most popular back-end programming languages for website development because it creates dynamic, interactive content for otherwise static web pages. 

Browser Extensions

JavaScript is the go-to language for creating browser extensions that add extra functionality to web browsers. These extensions can customize browser behavior, block ads, improve productivity, and integrate with other web services.

Game Development

JavaScript, along with HTML5 canvas and WebGL, allows for the development of browser-based games, such as Hero Wars and Forge of Empires. It’s robust enough to handle the rigors of online gaming demands like game logic, user input, graphics, and animations.

Learn More: The Best Programming Languages for Game Development

Server-Side Development

When used as a front-end development language, JavaScript enables building scalable and efficient server applications, APIs, and even full-stack web development.

Start Developing Your Programming Skills with App Academy

While we don’t currently offer TypeScript as part of our curriculum at At App Academy, we do offer a comprehensive curriculum that covers JavaScript and a number of other foundational programming languages. We provide structured learning, real-world projects, and a supportive learning environment to help you learn faster, without sacrificing quality of curriculum.

We aim to equip you with the skills needed to take your career to the next level. Schedule a call with an App Academy admissions counselor to learn more about our programs. And, if you’re ready to dig in deeper, start exploring our programs to see which one might be a good fit for you!

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