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# Global Polyfills
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Install web standard global APIs in Node.js environments to enable compatibility with web-standard code.
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## Capabilities
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### Install Globals
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Installs global polyfills for web standards in Node.js environments using either undici or @remix-run/web-fetch.
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```typescript { .api }
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/**
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 * Install web standard global APIs in Node.js environments
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 * @param options - Configuration options
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 * @param options.nativeFetch - If true, use undici's native fetch; otherwise use @remix-run/web-fetch (default: false)
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 */
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function installGlobals(options?: { nativeFetch?: boolean }): void;
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```
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**Installed Globals:**
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- `global.fetch` - Fetch API for making HTTP requests
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- `global.Request` - Request constructor for creating request objects
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- `global.Response` - Response constructor for creating response objects
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- `global.Headers` - Headers constructor for managing HTTP headers
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- `global.FormData` - FormData constructor for handling form data
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- `global.File` - File constructor for file handling
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**Note:** ReadableStream and WritableStream are declared in TypeScript types for better IDE support but are not polyfilled by this function.
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**Usage Examples:**
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```typescript
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import { installGlobals } from "@remix-run/node";
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// Install globals using @remix-run/web-fetch (default)
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installGlobals();
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// Now you can use web standard APIs
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const response = await fetch("https://api.example.com/data");
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const data = await response.json();
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// Install globals using undici's native fetch
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installGlobals({ nativeFetch: true });
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// Use undici's faster native implementation
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const response = await fetch("https://api.example.com/data");
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```
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**Implementation Details:**
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When `nativeFetch: false` (default), uses `@remix-run/web-fetch` polyfills:
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- Provides consistent behavior across Node.js versions
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- Full compatibility with web standards
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- Suitable for most applications
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When `nativeFetch: true`, uses undici's native implementations:
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- Better performance for high-throughput applications
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- Native Node.js implementation
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- Requires Node.js 18+ for optimal compatibility
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**Environment Configuration:**
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The function extends Node.js global types to include web standard APIs:
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```typescript { .api }
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declare global {
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  namespace NodeJS {
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    interface Global {
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      File: typeof File;
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      Headers: typeof Headers;
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      Request: typeof Request;
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      Response: typeof Response;
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      fetch: typeof fetch;
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      FormData: typeof FormData;
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      ReadableStream: typeof ReadableStream;
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      WritableStream: typeof WritableStream;
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    }
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  }
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  interface RequestInit {
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    duplex?: "half";
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  }
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}
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```
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**Note:** The TypeScript declarations include ReadableStream and WritableStream for IDE support, but only fetch, Request, Response, Headers, FormData, and File are actually installed as globals.