Typescript and Javascript - an introduction

Posted on January 7, 2024  (Last modified on June 16, 2025) • 2 min read • 411 words

Video is in Swedish

Introduction to TypeScript and JavaScript  

As developers, we’re constantly looking for ways to improve our coding experience and create more maintainable, scalable, and efficient software. Two programming languages that have gained immense popularity in recent years are JavaScript (JS) and its statically-typed cousin, TypeScript (TS). In this article, we’ll delve into the world of TypeScript and explore how it differs from JavaScript.

What is JavaScript?  

JavaScript is a high-level, dynamic, and interpreted programming language developed by Brendan Eich in 1995. It’s primarily used for client-side scripting on the web, allowing developers to create interactive web pages, web applications, and mobile applications. JavaScript is known for its flexibility, ease of use, and widespread adoption.

What is TypeScript?  

TypeScript is a statically-typed superset of JavaScript developed by Microsoft in 2012. It’s designed to help developers catch errors early on, improve code maintainability, and provide better tooling support. TypeScript adds optional static typing and other features to the JavaScript language, making it more suitable for large-scale applications.

Key differences between JavaScript and TypeScript  

1. Statically-typed vs Dynamically-typed: JavaScript is dynamically-typed, which means that the data type of a variable is determined at runtime. In contrast, TypeScript is statically-typed, allowing developers to specify the data types of variables before runtime.
2. Type annotations: TypeScript requires type annotations for variables, function parameters, and return types, whereas JavaScript does not have built-in support for type annotations.
3. Error prevention: TypeScript’s static typing helps prevent errors at compile-time, reducing the likelihood of runtime errors.
4. Tooling support: TypeScript provides better tooling support, including code completion, debugging, and error reporting.

When to use each language  

1. Use JavaScript when:
   • You’re building a small-scale web application or a quick prototype.
   • You need to work with legacy codebases that don’t support TypeScript.
   • You prefer the flexibility of dynamically-typed languages.
2. Use TypeScript when:
   • You’re building a large-scale, complex application that requires robust error handling and maintainability.
   • You want to take advantage of advanced tooling support and better code completion.
   • You need to ensure compatibility with existing JavaScript libraries and frameworks.

Conclusion  

In conclusion, both JavaScript and TypeScript are powerful programming languages with their own strengths and weaknesses. While JavaScript is ideal for small-scale projects or legacy codebases, TypeScript is a better choice for large-scale applications that require robust error handling and maintainability. By understanding the differences between these two languages, developers can make informed decisions about which language to use for their next project.

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