astro/packages/integrations/cloudflare/README.md

# @astrojs/cloudflare

An SSR adapter for use with Cloudflare Pages Functions targets. Write your code in Astro/Javascript and deploy to Cloudflare Pages.

In your `astro.config.mjs` use:

```js
import { defineConfig } from 'astro/config';
import cloudflare from '@astrojs/cloudflare';

export default defineConfig({
  output: 'server',
  adapter: cloudflare()
});
```

## Enabling Preview

In order for preview to work you must install `wrangler`

```sh
$ pnpm install wrangler --save-dev
```

It's then possible to update the preview script in your `package.json` to `"preview": "wrangler pages dev ./dist"`

## Streams

Some integrations such as [React](https://github.com/withastro/astro/tree/main/packages/integrations/react) rely on web streams. Currently Cloudflare Pages functions are in beta and don't support the `streams_enable_constructors` feature flag.

In order to work around this:
- install the `"web-streams-polyfill"` package
- add `import "web-streams-polyfill/es2018";` to the top of the front matter of every page which requires streams, such as server rendering a React component.