TypeScript 5.0: Embracing ECMAScript Modules for Enhanced Development
TypeScript 5.0, set to be released by Microsoft on March 16, represents a significant overhaul by restructuring the language around ECMAScript modules. This infrastructure change aims to align TypeScript more closely with modern JavaScript practices, making it easier for developers to utilize the latest features and improvements in both languages. Currently in the release candidate stage, TypeScript 5.0 will require users to run a minimum of Node.js 12 to leverage the benefits of this update.
One of the most notable enhancements in TypeScript 5.0 is the reduction in package size, which has decreased by approximately 46%. This reduction is expected to result in faster npm installs and less space consumption on developers’ systems. Moreover, the new version promises improved performance, with build times cut by 10% to 25%. However, for API consumers of TypeScript, these changes should not have a significant impact, as the core functionalities will remain intact.
Despite the shift towards ECMAScript modules, TypeScript will continue to provide a CommonJS-authored API. This means that existing build scripts and workflows will still function without requiring immediate updates, allowing developers to transition smoothly into the new module system. The decision to retain CommonJS support acknowledges the widespread use of this module system in the ecosystem while easing the path for gradual adoption of ECMAScript modules.
Historically, the TypeScript codebase has relied on namespaces instead of modules, a choice made before ECMAScript modules were standardized in 2015. At that time, there were uncertainties about compatibility with other module systems and a perceived lack of benefits. While namespaces provided useful features, such as file scope merging, they introduced runtime performance issues and did not reflect how most developers were writing their TypeScript code. By adopting ECMAScript modules, TypeScript 5.0 aims to rectify these limitations and offer a more streamlined, efficient development experience that resonates with modern JavaScript practices