The evolution of JavaScript modularization has led to a complex ecosystem involving various module formats like AMD, CommonJS, and ES modules, each with specific use cases and compatibility requirements. While browsers have gradually adopted ES modules since their introduction in the ES2015 specification, Node.js has historically relied on CommonJS but has been transitioning to support ES modules, offering developers the flexibility to use both types in tandem. This shift aims to harmonize client-server JavaScript development by allowing full-stack developers to write modular code more naturally. Node.js has been working towards a seamless integration of ES modules, reflected in the progressive implementation phases and the introduction of features like the ".mjs" file extension and import/export syntax. Key developments include a new module loader system that supports ES module and CommonJS interoperability and a proposal to support dual-mode packages for backward compatibility. Despite ongoing debates and challenges, the Node.js community continues to work towards a future where ES modules may eventually replace CommonJS, fostering a unified JavaScript modular experience across platforms.