React Type 'Element' not assignable to 'ReactNode' in Vite

When creating React apps with TypeScript in Vite, you might encounter the error Type 'Element' is not assignable to type 'ReactNode'. This occurs in development environments like VS Code despite the app running correctly in the browser. Common causes include outdated or conflicting type definitions and misconfigured TS settings.

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Solution 1: Update React Type Definitions

Most cases are resolved by updating React’s type definitions:

1. Install the latest @types/react and @types/react-dom:

npm install -D @types/react@latest @types/react-dom@latest
# or
yarn add -D @types/react@latest @types/react-dom@latest

2. Ensure package.json lists these versions under devDependencies:

{
  "devDependencies": {
    "@types/react": "^18.2.x",
    "@types/react-dom": "^18.2.x"
  }
}

3. If peer dependency conflicts arise:

npm install --legacy-peer-deps

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Solution 2: Correct tsconfig.json Settings

Misconfigured TypeScript settings can trigger this error:

Include "dom" in compilerOptions.lib:

{
  "compilerOptions": {
    "lib": [
      "dom",
      "dom.iterable",
      "esnext"
    ],
    "moduleResolution": "Bundler", // Required for Vite
    "jsx": "react-jsx"
  }
}

• Key Fixes:
  • "lib": ["dom", ...] ensures DOM types are recognized.
  • "moduleResolution": "Bundler" aligns with Vite's resolver.

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Solution 3: Clear VS Code Cache

VS Code’s cached TypeScript data may cause false positives:

1. Open the command palette (Ctrl/Cmd + Shift + P).
2. Run TypeScript: Restart TS Server.
3. Alternatively, reload VS Code's window (Ctrl/Cmd + Shift + P > Developer: Reload Window).

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Solution 4: Reinstall Type Definitions

Inconsistent installations can corrupt types:

npm uninstall @types/react @types/react-dom
npm install -D @types/react @types/react-dom

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Additional Checks

• Peer Dependencies: Ensure indirect dependencies like @types/prop-types are compatible (e.g., ≥15.7.8).
• TypeScript Version: Verify compatibility between your TypeScript version and React types (e.g., TS 5.1.6+).

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Why This Happens

TypeScript 5.1+ introduced stricter type checks for React nodes. Vite projects default to moduleResolution: "Bundler", which can conflict with outdated @types/react definitions. Explicitly updating types and aligning TS configs resolves these mismatches.

Final Tip: After implementing fixes, restart your IDE and development server to ensure changes take effect.