開始一個新的 React 專案

You can definitely use React without a framework—that’s how you’d use React for a part of your page. However, if you’re building a new app or a site fully with React, we recommend using a framework.

Here’s why.

Even if you don’t need routing or data fetching at first, you’ll likely want to add some libraries for them. As your JavaScript bundle grows with every new feature, you might have to figure out how to split code for every route individually. As your data fetching needs get more complex, you are likely to encounter server-client network waterfalls that make your app feel very slow. As your audience includes more users with poor network conditions and low-end devices, you might need to generate HTML from your components to display content early—either on the server, or during the build time. Changing your setup to run some of your code on the server or during the build can be very tricky.

These problems are not React-specific. This is why Svelte has SvelteKit, Vue has Nuxt, and so on. To solve these problems on your own, you’ll need to integrate your bundler with your router and with your data fetching library. It’s not hard to get an initial setup working, but there are a lot of subtleties involved in making an app that loads quickly even as it grows over time. You’ll want to send down the minimal amount of app code but do so in a single client–server roundtrip, in parallel with any data required for the page. You’ll likely want the page to be interactive before your JavaScript code even runs, to support progressive enhancement. You may want to generate a folder of fully static HTML files for your marketing pages that can be hosted anywhere and still work with JavaScript disabled. Building these capabilities yourself takes real work.

React frameworks on this page solve problems like these by default, with no extra work from your side. They let you start very lean and then scale your app with your needs. Each React framework has a community, so finding answers to questions and upgrading tooling is easier. Frameworks also give structure to your code, helping you and others retain context and skills between different projects. Conversely, with a custom setup it’s easier to get stuck on unsupported dependency versions, and you’ll essentially end up creating your own framework—albeit one with no community or upgrade path (and if it’s anything like the ones we’ve made in the past, more haphazardly designed).

If your app has unusual constraints not served well by these frameworks, or you prefer to solve these problems yourself, you can roll your own custom setup with React. Grab react and react-dom from npm, set up your custom build process with a bundler like Vite or Parcel, and add other tools as you need them for routing, static generation or server-side rendering, and more.

Next.js 的 App Router bundler 完全實作了官方的 React Server Components 規範。這讓你可以在單個 React tree 中混合 build-time、server-only 和和互動式元件。

例如，你可以將一個 server-only 的 React component 撰寫為 async 函式，該函式從資料庫或文件中讀取資料。然後，你可以將資料從該 component 傳遞給互動式 component：

// This component runs *only* on the server (or during the build).
async function Talks({ confId }) {
  // 1. You're on the server, so you can talk to your data layer. API endpoint not required.
  const talks = await db.Talks.findAll({ confId });

  // 2. Add any amount of rendering logic. It won't make your JavaScript bundle larger.
  const videos = talks.map(talk => talk.video);

  // 3. Pass the data down to the components that will run in the browser.
  return <SearchableVideoList videos={videos} />;
}

Next.js 的 App Router 也整合了使用 Suspense 進行 data fetching。這讓你可以直接在 React tree 中為使用者介面不同部分指定載入狀態（例如：skeleton placeholder）：

<Suspense fallback={<TalksLoading />}>
  <Talks confId={conf.id} />
</Suspense>

Server Components 和 Suspense 是 React 的功能，而不是 Next.js 的。然而，在框架層面採用它們需要計畫和以及複雜的實現工作。目前，Next.js APP Router 是最完整的實現方式。React 團隊正在與 bundler開發人員合作，使這些功能在下一代框架中更容易實現。