Agent Skills
› fanfan-de/anybox
› use-dom
use-dom
GitHub在Expo中通过DOM组件在原生平台WebView内运行Web代码，支持使用纯Web库、迁移现有Web组件及处理复杂HTML/CSS布局。
Trigger Scenarios
需要在原生应用中集成Web专属库（如图表、语法高亮）
将现有的React Web组件迁移至Expo原生应用
需要实现复杂的HTML/CSS布局或嵌入iframe/WebGL内容
Install
npx skills add fanfan-de/anybox --skill use-dom -g -y
SKILL.md
Frontmatter
{
"name": "use-dom",
"license": "MIT",
"version": "1.0.0",
"description": "Use Expo DOM components to run web code in a webview on native and as-is on web. Migrate web code to native incrementally."
}
What are DOM Components?
DOM components allow web code to run verbatim in a webview on native platforms while rendering as-is on web. This enables using web-only libraries like recharts, react-syntax-highlighter, or any React web library in your Expo app without modification.
When to Use DOM Components
Use DOM components when you need:
- Web-only libraries — Charts (recharts, chart.js), syntax highlighters, rich text editors, or any library that depends on DOM APIs
- Migrating web code — Bring existing React web components to native without rewriting
- Complex HTML/CSS layouts — When CSS features aren't available in React Native
- iframes or embeds — Embedding external content that requires a browser context
- Canvas or WebGL — Web graphics APIs not available natively
When NOT to Use DOM Components
Avoid DOM components when:
- Native performance is critical — Webviews add overhead
- Simple UI — React Native components are more efficient for basic layouts
- Deep native integration — Use local modules instead for native APIs
- Layout routes —
_layoutfiles cannot be DOM components
Basic DOM Component
Create a new file with the 'use dom'; directive at the top:
// components/WebChart.tsx
"use dom";
export default function WebChart({
data,
}: {
data: number[];
dom: import("expo/dom").DOMProps;
}) {
return (
<div style={{ padding: 20 }}>
<h2>Chart Data</h2>
<ul>
{data.map((value, i) => (
<li key={i}>{value}</li>
))}
</ul>
</div>
);
}
Rules for DOM Components
- Must have
'use dom';directive at the top of the file - Single default export — One React component per file
- Own file — Cannot be defined inline or combined with native components
- Serializable props only — Strings, numbers, booleans, arrays, plain objects
- Include CSS in the component file — DOM components run in isolated context
The dom Prop
Every DOM component receives a special dom prop for webview configuration. Always type it in your props:
"use dom";
interface Props {
content: string;
dom: import("expo/dom").DOMProps;
}
export default function MyComponent({ content }: Props) {
return <div>{content}</div>;
}
Common dom Prop Options
// Disable body scrolling
<DOMComponent dom={{ scrollEnabled: false }} />
// Flow under the notch (disable safe area insets)
<DOMComponent dom={{ contentInsetAdjustmentBehavior: "never" }} />
// Control size manually
<DOMComponent dom={{ style: { width: 300, height: 400 } }} />
// Combine options
<DOMComponent
dom={{
scrollEnabled: false,
contentInsetAdjustmentBehavior: "never",
style: { width: '100%', height: 500 }
}}
/>
Exposing Native Actions to the Webview
Pass async functions as props to expose native functionality to the DOM component:
// app/index.tsx (native)
import { Alert } from "react-native";
import DOMComponent from "@/components/dom-component";
export default function Screen() {
return (
<DOMComponent
showAlert={async (message: string) => {
Alert.alert("From Web", message);
}}
saveData={async (data: { name: string; value: number }) => {
// Save to native storage, database, etc.
console.log("Saving:", data);
return { success: true };
}}
/>
);
}
// components/dom-component.tsx
"use dom";
interface Props {
showAlert: (message: string) => Promise<void>;
saveData: (data: {
name: string;
value: number;
}) => Promise<{ success: boolean }>;
dom?: import("expo/dom").DOMProps;
}
export default function DOMComponent({ showAlert, saveData }: Props) {
const handleClick = async () => {
await showAlert("Hello from the webview!");
const result = await saveData({ name: "test", value: 42 });
console.log("Save result:", result);
};
return <button onClick={handleClick}>Trigger Native Action</button>;
}
Using Web Libraries
DOM components can use any web library:
// components/syntax-highlight.tsx
"use dom";
import SyntaxHighlighter from "react-syntax-highlighter";
import { docco } from "react-syntax-highlighter/dist/esm/styles/hljs";
interface Props {
code: string;
language: string;
dom?: import("expo/dom").DOMProps;
}
export default function SyntaxHighlight({ code, language }: Props) {
return (
<SyntaxHighlighter language={language} style={docco}>
{code}
</SyntaxHighlighter>
);
}
// components/chart.tsx
"use dom";
import {
LineChart,
Line,
XAxis,
YAxis,
CartesianGrid,
Tooltip,
} from "recharts";
interface Props {
data: Array<{ name: string; value: number }>;
dom: import("expo/dom").DOMProps;
}
export default function Chart({ data }: Props) {
return (
<LineChart width={400} height={300} data={data}>
<CartesianGrid strokeDasharray="3 3" />
<XAxis dataKey="name" />
<YAxis />
<Tooltip />
<Line type="monotone" dataKey="value" stroke="#8884d8" />
</LineChart>
);
}
CSS in DOM Components
CSS imports must be in the DOM component file since they run in isolated context:
// components/styled-component.tsx
"use dom";
import "@/styles.css"; // CSS file in same directory
export default function StyledComponent({
dom,
}: {
dom: import("expo/dom").DOMProps;
}) {
return (
<div className="container">
<h1 className="title">Styled Content</h1>
</div>
);
}
Or use inline styles / CSS-in-JS:
"use dom";
const styles = {
container: {
padding: 20,
backgroundColor: "#f0f0f0",
},
title: {
fontSize: 24,
color: "#333",
},
};
export default function StyledComponent({
dom,
}: {
dom: import("expo/dom").DOMProps;
}) {
return (
<div style={styles.container}>
<h1 style={styles.title}>Styled Content</h1>
</div>
);
}
Expo Router in DOM Components
The expo-router <Link /> component and router API work inside DOM components:
"use dom";
import { Link, useRouter } from "expo-router";
export default function Navigation({
dom,
}: {
dom: import("expo/dom").DOMProps;
}) {
const router = useRouter();
return (
<nav>
<Link href="/about">About</Link>
<button onClick={() => router.push("/settings")}>Settings</button>
</nav>
);
}
Router APIs That Require Props
These hooks don't work directly in DOM components because they need synchronous access to native routing state:
useLocalSearchParams()useGlobalSearchParams()usePathname()useSegments()useRootNavigation()useRootNavigationState()
Solution: Read these values in the native parent and pass as props:
// app/[id].tsx (native)
import { useLocalSearchParams, usePathname } from "expo-router";
import DOMComponent from "@/components/dom-component";
export default function Screen() {
const { id } = useLocalSearchParams();
const pathname = usePathname();
return <DOMComponent id={id as string} pathname={pathname} />;
}
// components/dom-component.tsx
"use dom";
interface Props {
id: string;
pathname: string;
dom?: import("expo/dom").DOMProps;
}
export default function DOMComponent({ id, pathname }: Props) {
return (
<div>
<p>Current ID: {id}</p>
<p>Current Path: {pathname}</p>
</div>
);
}
Detecting DOM Environment
Check if code is running in a DOM component:
"use dom";
import { IS_DOM } from "expo/dom";
export default function Component({
dom,
}: {
dom?: import("expo/dom").DOMProps;
}) {
return <div>{IS_DOM ? "Running in DOM component" : "Running natively"}</div>;
}
Assets
Prefer requiring assets instead of using the public directory:
"use dom";
// Good - bundled with the component
const logo = require("../assets/logo.png");
export default function Component({
dom,
}: {
dom: import("expo/dom").DOMProps;
}) {
return <img src={logo} alt="Logo" />;
}
Usage from Native Components
Import and use DOM components like regular components:
// app/index.tsx
import { View, Text } from "react-native";
import WebChart from "@/components/web-chart";
import CodeBlock from "@/components/code-block";
export default function HomeScreen() {
return (
<View style={{ flex: 1 }}>
<Text>Native content above</Text>
<WebChart data={[10, 20, 30, 40, 50]} dom={{ style: { height: 300 } }} />
<CodeBlock
code="const x = 1;"
language="javascript"
dom={{ scrollEnabled: true }}
/>
<Text>Native content below</Text>
</View>
);
}
Platform Behavior
| Platform | Behavior |
|---|---|
| iOS | Rendered in WKWebView |
| Android | Rendered in WebView |
| Web | Rendered as-is (no webview wrapper) |
On web, the dom prop is ignored since no webview is needed.
Tips
- DOM components hot reload during development
- Keep DOM components focused — don't put entire screens in webviews
- Use native components for navigation chrome, DOM components for specialized content
- Test on all platforms — web rendering may differ slightly from native webviews
- Large DOM components may impact performance — profile if needed
- The webview has its own JavaScript context — cannot directly share state with native
Version History
- 08dc189 Current 2026-07-05 18:57
