Learning React (2nd Edition)

This book is the Chinese edition of the second edition of O'Reilly's classic front-end technology book Learning React, aimed at developers who already write JavaScript and know the basics of HTML and CSS but have not yet systematically encountered React or functional JavaScript. The book has 12 chapters; the first half spends considerable space re-teaching syntax fundamentals: variable declarations since ES6, template strings, default parameters, arrow functions, destructuring assignment, the spread operator, Promises, classes, and modules, then moves into core concepts of functional programming, including immutability, pure functions, data transformation, higher-order functions, recursion, and composition. Only after laying a solid language foundation does the book turn to React itself: the meaning of the virtual DOM and React elements, setting up a build process with JSX, Babel, and webpack, components, props, state, and the component tree, property validation, refs and the reverse flow of data, then the component lifecycle, making requests with fetch, integrating third-party libraries such as D3, higher-order components, and the ideas behind Flux. The second half unfolds in turn Redux (actions, reducers, stores, middleware), React Redux's Provider and connect, testing and snapshot testing with ESLint and Jest, React Router's routing and nested routes, and finally server-side rendering and isomorphic (universal) applications. The whole book ties the code of each chapter together with a single running color-management example, making it a rare React tutorial that builds completely "from language to architecture." Compared with the first edition, this edition adds explanations of modern approaches such as Hooks.