Adapter Configuration

import { Adapter } from '@sveltejs/kit';
import { GetPlatformProxyOptions } from 'wrangler';

/**
 * Creates a SvelteKit adapter for Cloudflare deployment
 * @param options - Configuration options for the adapter
 * @returns SvelteKit Adapter instance
 */
function adapter(options?: AdapterOptions): Adapter;

// Basic usage with default settings
import adapter from "@sveltejs/adapter-cloudflare";

export default {
  kit: {
    adapter: adapter()
  }
};

// With custom configuration
export default {
  kit: {
    adapter: adapter({
      config: './custom-wrangler.toml',
      fallback: 'spa',
      routes: {
        include: ['/*'],
        exclude: ['<all>']
      }
    })
  }
};

interface AdapterOptions {
  /**
   * Path to your Wrangler configuration file
   * @see https://developers.cloudflare.com/workers/wrangler/configuration/
   */
  config?: string;
  
  /**
   * Whether to render a plaintext 404.html page or a rendered SPA fallback page
   * for non-matching asset requests.
   *
   * For Cloudflare Workers, the default behaviour is to return a null-body
   * 404-status response for non-matching assets requests. However, if the
   * assets.not_found_handling Wrangler configuration setting is set to "404-page",
   * this page will be served if a request fails to match an asset. If 
   * assets.not_found_handling is set to "single-page-application", the adapter 
   * will render a SPA fallback index.html page regardless of the fallback option specified.
   *
   * For Cloudflare Pages, this page will only be served when a request that
   * matches an entry in routes.exclude fails to match an asset.
   *
   * Most of the time 'plaintext' is sufficient, but if you are using routes.exclude 
   * to manually exclude a set of prerendered pages without exceeding the 100 route 
   * limit, you may wish to use 'spa' instead to avoid showing an unstyled 404 page 
   * to users.
   *
   * @see https://developers.cloudflare.com/pages/configuration/serving-pages/#not-found-behavior
   * @default 'plaintext'
   */
  fallback?: 'plaintext' | 'spa';
  
  /**
   * Only for Cloudflare Pages. Customize the automatically-generated _routes.json file.
   * @see https://developers.cloudflare.com/pages/platform/functions/routing/#create-a-_routesjson-file
   */
  routes?: {
    /**
     * Routes that will be invoked by functions. Accepts wildcards.
     * @default ["/*"]
     */
    include?: string[];
    
    /**
     * Routes that will not be invoked by functions. Accepts wildcards.
     * exclude takes priority over include.
     * 
     * To have the adapter automatically exclude certain things, you can use these placeholders:
     * - <build> to exclude build artifacts (files generated by Vite)
     * - <files> for the contents of your static directory
     * - <prerendered> for prerendered routes
     * - <all> to exclude all of the above
     * 
     * @default ["<all>"]
     */
    exclude?: string[];
  };
  
  /**
   * Config object passed to getPlatformProxy during development and preview.
   * @see https://developers.cloudflare.com/workers/wrangler/api/#getplatformproxy
   */
  platformProxy?: GetPlatformProxyOptions;
}

// Custom routing configuration
adapter({
  routes: {
    include: ['/*'],
    exclude: [
      '<build>',
      '<files>',
      '/api/static/*',
      '/public/*'
    ]
  }
});

// Minimal function routing
adapter({
  routes: {
    include: ['/api/*', '/auth/*'],
    exclude: ['<all>']
  }
});

// For SPA applications
adapter({
  fallback: 'spa'
});

// For traditional server-rendered apps
adapter({
  fallback: 'plaintext'
});