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# Preface

Welcome to *Foundations of High-Performance React Applications* where we build our own simplified version of React. We’ll use our React to gain an understanding of the real React and how to build high-performance applications with it. 

This book is based on the first chapter of the book *High-Performance React*. If you enjoy this book and you want to learn more practical ways to utilize the foundations we’ll learn here and get a more detailed blueprint for creating high performance React applications, then be sure to check out *High-Performance React*. 

This book is not intended to be an introduction to React or JavaScript. While it might be useful to beginners, this book assumes familiarity with both JavaScript and React. 

And while this book only specifically addresses React-DOM, the foundations apply equally to React-Native and other React implementations because they are all based on the same core React library and algorithms. 

The code in this book is clear and simple so as to best communicate the algorithms we’ll be exploring. It is not intended to be used in production, but it is functional. I think you’ll likely find it useful to follow along by writing the code yourself. It will help you better understand how it works, and even more critically, it will allow you to play with it and test how the algorithms work with your own examples. 

Even if you don't write out the code yourself and, instead, read through this book more like a novel, I believe the fundamentals will still stick with you and provide value in your React programs-to-come. 

I'm very excited to take you on this journey with me and, so, now it's time to learn what lies at the very foundation of React. 


