CppNorth, The Canadian C++ Conference 2025

The integration of C++20's new ranges library into JavaScript runtimes presents a promising avenue for enhancing performance and code clarity. We delves into how ranges can simplify the handling of collections and sequences in JavaScript engines such as Node.js and Cloudflare workerd. By leveraging lazy evaluation offered by C++20 ranges, JavaScript runtimes can achieve more efficient data processing, reducing both memory footprint and execution time. We explore the application of ranges in optimizing Node.js, showing how they can be used for tasks such as data transformation, filtering, and iteration with less boilerplate code. We examine the benefits of ranges in terms of code readability and maintainability, which are critical for the large teams working on these engines. We provide practical guidance on how developers can begin to incorporate ranges into their projects, considering both the technical and educational aspects of this transition. Our analysis concludes that while there's an adjustment period for developers, the long-term advantages in performance and ease of development make C++20 ranges an invaluable tool for modernizing JavaScript runtimes.