ReScript: A Better Typed JavaScript? (with Gabriel Nordeborn)
Feb 20, 2025
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Gabriel Nordeborn, a compiler contributor for ReScript, discusses the strengths and advantages of ReScript compared to TypeScript. He unpacks why JavaScript developers might want to choose ReScript, focusing on its streamlined type system and performance. The conversation touches on the challenges of TypeScript, highlights ReScript’s efficiencies in immutability and pattern matching, and explores methods for enhancing developer productivity. Gabriel also shares insights on the importance of achieving a flow state for optimal coding creativity.
ReScript offers a sound type system and a new syntax designed for JavaScript developers, emphasizing familiarity and ease of transition.
With superior compilation speed, ReScript enhances the development experience by providing faster feedback loops that boost productivity and efficiency.
Integrating functional programming principles, ReScript supports immutability and exhaustiveness checking, facilitating safer and more manageable coding practices for developers.
Deep dives
The Evolution of JavaScript Alternatives
There has been considerable interest in developing alternatives to JavaScript due to its rushed design and the desire for a more polished programming experience. Many developers initially sought languages like CoffeeScript to address the limitations they found in JavaScript. Over time, TypeScript emerged as a significant success story by providing type safety while largely retaining the JavaScript syntax and features that developers were accustomed to. However, many still believe that there remains a substantial demand for further exploration of alternative programming languages like Rescript.
Understanding Rescript
Rescript is defined as a programming language compiling to JavaScript, designed to optimize the JavaScript writing experience while integrating seamlessly with existing JavaScript ecosystems. Unlike TypeScript, which adds types to JavaScript, Rescript takes a different approach by leveraging its roots in OCaml to create a new syntax that aims for maximum familiarity with JavaScript users. It focuses on providing a sound type system while efficiently compiling to clean JavaScript output, thus facilitating better performance during execution. This unique angle allows developers to enjoy the best of both worlds, utilizing a robust type system while still working in a familiar landscape.
Performance Advantages of Rescript
One of the most notable benefits of using Rescript is its superior compilation speed compared to TypeScript, which can lead to a better development experience, especially in larger projects. TypeScript, while powerful, often introduces performance overhead due to its extensive type system and type-checking processes, which can slow down build time and IDE responsiveness. In contrast, Rescript aims to provide a faster feedback loop for developers, thus minimizing distractions and keeping them in a productive flow state while coding. This speed advantage also enhances the developer experience, allowing for quicker iterations and increased productivity.
Enhanced Developer Experience
Rescript integrates a functional programming paradigm while maintaining ease of use for JavaScript developers, enabling them to work with familiar structures yet enjoy the advantages of functional programming. One of its significant features is the implementation of immutability by default, reducing the chances of unintended mutations in code. Additionally, exhaustiveness checking is natively handled, ensuring that developers can manage different cases efficiently without oversight. This focus on developer experience underscores Rescript's goal of being both productive and beginner-friendly, supporting a smooth transition for those coming from JavaScript or TypeScript backgrounds.
Interfacing with JavaScript Libraries
Rescript is designed to work seamlessly with existing JavaScript libraries and frameworks, making it an attractive option for developers looking to enhance their current projects without a complete overhaul. This versatility allows developers to import JavaScript code and combine it with Rescript, enabling them to leverage their existing codebases while adopting the newer features of Rescript. However, the initial setup may require writing bindings for libraries that do not have native support, which can be a barrier for some. Still, the integration process is relatively straightforward, promoting an efficient workflow between the two languages.
The Road Ahead for Rescript
Looking ahead, the development team behind Rescript is focused on further refining the language and enhancing its features. Plans include streamlining the language to create a more cohesive experience, particularly in areas such as compiling to JavaScript and improving error handling. Upgrading to the next version aims to alleviate any remaining learning curves for new users and remove outdated functionality that may no longer serve the project's goals. As Rescript continues to grow, the commitment to fostering a friendly developer experience remains a cornerstone of its evolution.
ReScript is a strongly-typed programming language that compiles to JavaScript, and that puts it squarely in competition with TypeScript. So why would a JavaScript developer choose to learn it next? What does it offer that makes it a tempting proposition? And how are the ReScript developers making life easier for anyone who wants to make the switch?
To answer all these questions and more, I’m joined this week by Gabriel Nordeborn, one of ReScript’s compiler contributors.
