Synapse: Skill for Claude Code

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 — _layout files 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

1. Must have 'use dom'; directive at the top of the file
2. Single default export — One React component per file
3. Own file — Cannot be defined inline or combined with native components
4. Serializable props only — Strings, numbers, booleans, arrays, plain objects
5. Include CSS in the component file — DOM components run in isolated context

The dom Prop