This book is a step-by-step guide for developers to build custom Excel functions with JavaScript. Beginning with the installation of tools like Node.js and Git, it explores setting up Microsoft Script Lab, building add-ins, and understanding essential file structures. Readers will learn to create and debug custom functions, handle asynchronous data, and integrate streaming web services. The book progresses through practical examples, teaching developers to fetch data from APIs and use advanced techniques like batching and streaming for real-time Excel updates. It demystifies the JSON manifest, JavaScript function files, and debugging processes essential for successful add-in development. By the end, readers will have a robust understanding of creating custom Excel functions, optimizing workflows, and integrating dynamic web services. Whether you're an Excel enthusiast or an experienced developer, this book offers a practical, engaging pathway to enhance Excel functionality through coding.
