> ## Documentation Index
> Fetch the complete documentation index at: https://smartac-justin-client-exports.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# React

> 使用 JSX、状态和客户端逻辑，在你的 Mintlify 文档中通过自定义 React 组件构建交互且可复用的元素。

export const ColorGenerator = () => {
  const [hue, setHue] = useState(165);
  const [saturation, setSaturation] = useState(84);
  const [lightness, setLightness] = useState(31);
  const [colors, setColors] = useState([]);
  useEffect(() => {
    const newColors = [];
    for (let i = 0; i < 5; i++) {
      const l = Math.max(10, Math.min(90, lightness - 20 + i * 10));
      newColors.push(`hsl(${hue}, ${saturation}%, ${l}%)`);
    }
    setColors(newColors);
  }, [hue, saturation, lightness]);
  const copyToClipboard = color => {
    navigator.clipboard.writeText(color).then(() => {
      console.log(`Copied ${color} to clipboard!`);
    }).catch(err => {
      console.error("Failed to copy: ", err);
    });
  };
  return <div className="p-4 border dark:border-white/10 rounded-2xl not-prose">
      <div className="space-y-4">
        <div className="space-y-2">
          <label className="block text-sm text-zinc-950/70 dark:text-white/70">
            Hue: {hue}°
            <input type="range" min="0" max="360" value={hue} onChange={e => setHue(Number.parseInt(e.target.value))} className="w-full h-2 bg-zinc-950/20 rounded-lg appearance-none cursor-pointer dark:bg-white/20 mt-1" style={{
    background: `linear-gradient(to right, 
                  hsl(0, ${saturation}%, ${lightness}%), 
                  hsl(60, ${saturation}%, ${lightness}%), 
                  hsl(120, ${saturation}%, ${lightness}%), 
                  hsl(180, ${saturation}%, ${lightness}%), 
                  hsl(240, ${saturation}%, ${lightness}%), 
                  hsl(300, ${saturation}%, ${lightness}%), 
                  hsl(360, ${saturation}%, ${lightness}%))`
  }} />
          </label>

          <label className="block text-sm text-zinc-950/70 dark:text-white/70">
            Saturation: {saturation}%
            <input type="range" min="0" max="100" value={saturation} onChange={e => setSaturation(Number.parseInt(e.target.value))} className="w-full h-2 bg-zinc-950/20 rounded-lg appearance-none cursor-pointer dark:bg-white/20 mt-1" style={{
    background: `linear-gradient(to right, 
                  hsl(${hue}, 0%, ${lightness}%), 
                  hsl(${hue}, 50%, ${lightness}%), 
                  hsl(${hue}, 100%, ${lightness}%))`
  }} />
          </label>

          <label className="block text-sm text-zinc-950/70 dark:text-white/70">
            Lightness: {lightness}%
            <input type="range" min="0" max="100" value={lightness} onChange={e => setLightness(Number.parseInt(e.target.value))} className="w-full h-2 bg-zinc-950/20 rounded-lg appearance-none cursor-pointer dark:bg-white/20 mt-1" style={{
    background: `linear-gradient(to right, 
                  hsl(${hue}, ${saturation}%, 0%), 
                  hsl(${hue}, ${saturation}%, 50%), 
                  hsl(${hue}, ${saturation}%, 100%))`
  }} />
          </label>
        </div>

        <div className="flex space-x-2">
          {colors.map((color, idx) => <div key={idx} className="h-16 rounded flex-1 cursor-pointer transition-transform hover:scale-105" style={{
    backgroundColor: color
  }} title={`Click to copy: ${color}`} onClick={() => copyToClipboard(color)} />)}
        </div>

        <div className="text-sm font-mono text-zinc-950/70 dark:text-white/70">
          <p>
            Base color: hsl({hue}, {saturation}%, {lightness}%)
          </p>
        </div>
      </div>
    </div>;
};

直接在 MDX 文件中使用 [React 组件](https://react.dev) 和 [hooks](https://react.dev/reference/react/hooks) 在文档中构建交互式元素。

<div id="inline-components">
  ## 内联组件
</div>

直接在你的 MDX 文件中声明组件：

export const Counter = () => {
  const [count, setCount] = useState(0);
  const increment = () => setCount(count + 1);
  const decrement = () => setCount(count - 1);
  return <div className="flex items-center justify-center">
      <div className="flex items-center rounded-xl overflow-hidden border border-zinc-950/20 dark:border-white/20">
        <button onClick={decrement} className="flex items-center justify-center h-8 w-8 text-zinc-950/80 dark:text-white/80 border-r border-zinc-950/20 dark:border-white/20" aria-label="Decrease">
          -
        </button>

        <div className="flex text-sm items-center justify-center h-8 px-6 text-zinc-950/80 dark:text-white/80 font-medium min-w-[4rem] text-center">
          {count}
        </div>

        <button onClick={increment} className="flex items-center justify-center h-8 w-8 text-zinc-950/80 dark:text-white/80 border-l border-zinc-950/20 dark:border-white/20" aria-label="Increase">
          +
        </button>
      </div>
    </div>;
};

<Counter />

```mdx theme={null}
export const Counter = () => {
  const [count, setCount] = useState(0)
  const increment = () => setCount(count + 1)
  const decrement = () => setCount(count - 1)

  return (
    <div>
      <button onClick={decrement}>-</button>
      <span>{count}</span>
      <button onClick={increment}>+</button>
    </div>
  )
}

<Counter />
```

<div id="import-components">
  ## 导入组件
</div>

组件文件必须位于 `/snippets/` 文件夹中。更多信息请参阅 [可复用片段](/zh/create/reusable-snippets)。

<Note>
  不支持嵌套导入。请将所有被引用的组件直接导入到父 MDX 文件中。
</Note>

在 `snippets/` 中创建一个组件文件：

```mdx /snippets/color-generator.jsx [expandable] theme={null}
export const ColorGenerator = () => {
  const [hue, setHue] = useState(180)
  const [saturation, setSaturation] = useState(50)
  const [lightness, setLightness] = useState(50)
  const [colors, setColors] = useState([])

  useEffect(() => {
    const newColors = []
    for (let i = 0; i < 5; i++) {
      const l = Math.max(10, Math.min(90, lightness - 20 + i * 10))
      newColors.push(`hsl(${hue}, ${saturation}%, ${l}%)`)
    }
    setColors(newColors)
  }, [hue, saturation, lightness])

  const copyToClipboard = (color) => {
    navigator.clipboard
      .writeText(color)
      .then(() => {
        console.log(`Copied ${color} to clipboard!`)
      })
      .catch((err) => {
        console.error("Failed to copy: ", err)
      })
  }

  return (
    <div className="p-4 border dark:border-zinc-950/80 rounded-xl not-prose">
      <div className="space-y-4">
        <div className="space-y-2">
          <label className="block text-sm text-zinc-950/70 dark:text-white/70">
            Hue: {hue}°
            <input
              type="range"
              min="0"
              max="360"
              value={hue}
              onChange={(e) => setHue(Number.parseInt(e.target.value))}
              className="w-full h-2 bg-zinc-950/20 rounded-lg appearance-none cursor-pointer dark:bg-white/20 mt-1"
              style={{
                background: `linear-gradient(to right, 
                  hsl(0, ${saturation}%, ${lightness}%), 
                  hsl(60, ${saturation}%, ${lightness}%), 
                  hsl(120, ${saturation}%, ${lightness}%), 
                  hsl(180, ${saturation}%, ${lightness}%), 
                  hsl(240, ${saturation}%, ${lightness}%), 
                  hsl(300, ${saturation}%, ${lightness}%), 
                  hsl(360, ${saturation}%, ${lightness}%))`,
              }}
            />
          </label>

          <label className="block text-sm text-zinc-950/70 dark:text-white/70">
            Saturation: {saturation}%
            <input
              type="range"
              min="0"
              max="100"
              value={saturation}
              onChange={(e) => setSaturation(Number.parseInt(e.target.value))}
              className="w-full h-2 bg-zinc-950/20 rounded-lg appearance-none cursor-pointer dark:bg-white/20 mt-1"
              style={{
                background: `linear-gradient(to right, 
                  hsl(${hue}, 0%, ${lightness}%), 
                  hsl(${hue}, 50%, ${lightness}%), 
                  hsl(${hue}, 100%, ${lightness}%))`,
              }}
            />
          </label>

          <label className="block text-sm text-zinc-950/70 dark:text-white/70">
            Lightness: {lightness}%
            <input
              type="range"
              min="0"
              max="100"
              value={lightness}
              onChange={(e) => setLightness(Number.parseInt(e.target.value))}
              className="w-full h-2 bg-zinc-950/20 rounded-lg appearance-none cursor-pointer dark:bg-white/20 mt-1"
              style={{
                background: `linear-gradient(to right, 
                  hsl(${hue}, ${saturation}%, 0%), 
                  hsl(${hue}, ${saturation}%, 50%), 
                  hsl(${hue}, ${saturation}%, 100%))`,
              }}
            />
          </label>
        </div>

        <div className="flex space-x-1">
          {colors.map((color, idx) => (
            <div
              key={idx}
              className="h-16 rounded flex-1 cursor-pointer transition-transform hover:scale-105"
              style={{ backgroundColor: color }}
              title={`Click to copy: ${color}`}
              onClick={() => copyToClipboard(color)}
            />
          ))}
        </div>

        <div className="text-sm font-mono text-zinc-950/70 dark:text-white/70">
          <p>
            Base color: hsl({hue}, {saturation}%, {lightness}%)
          </p>
        </div>
      </div>
    </div>
  )
}
```

然后导入并使用它：

```mdx theme={null}
import { ColorGenerator } from "/snippets/color-generator.jsx"

<ColorGenerator />
```

<ColorGenerator />

<div id="considerations">
  ## 注意事项
</div>

* **SEO**：搜索引擎可能无法完全索引由客户端渲染的动态内容。
* **首次加载**：访客在组件渲染之前可能会看到闪烁。
* **可访问性**：确保屏幕阅读器能够播报动态内容的变化。
* **优化依赖数组**：仅在 `useEffect` 中包含必要的依赖。
* **缓存昂贵操作**：在适当之处使用 `useMemo` 或 `useCallback`。
* **减少重新渲染**：将大型组件拆分为较小的组件。
* **懒加载**：延迟渲染复杂组件，以缩短首次页面加载时间。由于 MDX 沙箱不支持 `React.lazy` 和动态 `import()`，请改为通过用户交互或可见性来控制重量级组件的加载。参见[延迟渲染重量级组件](#defer-rendering-for-heavy-components)。

<div id="defer-rendering-for-heavy-components">
  ### 延迟渲染重量级组件
</div>

MDX 沙箱中无法使用 `React.lazy`、`Suspense` 和动态 `import()`。为获得同样的效果，先渲染一个轻量级的占位符，仅在读者主动选择后再挂载开销较大的组件。这样可以保持首次页面加载的速度，同时仍然让读者能够与完整的组件交互。

下面的示例会让上一节中的 `ColorGenerator` 保持未挂载状态，直到读者点击 **Load color generator**：

export const LazyColorGenerator = () => {
  const [show, setShow] = useState(false);
  if (!show) {
    return <button onClick={() => setShow(true)} className="px-3 py-1.5 text-sm rounded-lg border border-zinc-950/20 dark:border-white/20 text-zinc-950/80 dark:text-white/80">
        Load color generator
      </button>;
  }
  return <ColorGenerator />;
};

<LazyColorGenerator />

```mdx theme={null}
import { ColorGenerator } from "/snippets/color-generator.jsx"

export const LazyColorGenerator = () => {
  const [show, setShow] = useState(false)

  if (!show) {
    return (
      <button onClick={() => setShow(true)}>
        Load color generator
      </button>
    )
  }

  return <ColorGenerator />
}

<LazyColorGenerator />
```

如需在组件滚动到可见区域后再进行渲染，可将按钮替换为在 `useEffect` 中设置的 `IntersectionObserver`。模式相同：在触发器触发之前保持 `show` 为 `false`，然后返回重量级组件。