React 是什麼？ React 是一個陳述式、高效且具有彈性的 JavaScript 函式庫，用以建立使用者介面。 它讓你使用小巧而獨立的「component」，來建立複雜的 UI。 React 有數種不同的 component，但讓 …

React makes it painless to create interactive UIs. Design simple views for each state in your application, and React will efficiently update and render just the right components when your data changes.

不管你是想初步嘗試 React、在簡單的 HTML 網頁上加入互動性，或是實作一個使用 React 驅動的複雜應用程式，這章節裏的連結會幫助你開始。

通过这篇教程，我们接触了 React 中的一些概念，比如 React 元素、React 组件、props，还有 state。 更多关于这些概念的细节的解释，参考 文档的其他部分。

このチュートリアルで学ぶ技法はどのような React のアプリにおいても基本的なものであり、マスターすることで React への深い理解が得られます。

In this guide, we will examine the building blocks of React apps: elements and components. Once you master them, you can create complex apps from small reusable pieces.

In React, mutable state is typically kept in the state property of components, and only updated with setState(). We can combine the two by making the React state be the “single source of truth”.

Hooks don’t replace your knowledge of React concepts. Instead, Hooks provide a more direct API to the React concepts you already know: props, state, context, refs, and lifecycle.

Conditional rendering in React works the same way conditions work in JavaScript. Use JavaScript operators like if or the conditional operator to create elements representing the current state, and let …

React will remember the function you passed (we’ll refer to it as our “effect”), and call it later after performing the DOM updates. In this effect, we set the document title, but we could also perform data …