feat(echo): add SvelteKit serve function

packages/echo/package.json

@@ -66,10 +66,16 @@
       "require": "./dist/h3.js",
       "import": "./dist/h3.mjs",
       "types": "./dist/h3.d.ts"
+    },
+    "./sveltekit": {
+      "require": "./dist/sveltekit.js",
+      "import": "./dist/sveltekit.mjs",
+      "types": "./dist/sveltekit.d.ts"
     }
   },
   "devDependencies": {
     "@jest/globals": "^29.7.0",
+    "@sveltejs/kit": "^2.5.10",
     "@types/express": "^4.17.13",
     "@types/jest": "^29.5.12",
     "@types/json-schema": "^7.0.15",

packages/echo/src/sveltekit.ts

@@ -0,0 +1,62 @@
+import { RequestEvent } from '@sveltejs/kit';
+import { EchoRequestHandler, ServeHandlerOptions } from './handler';
+import { type SupportedFrameworkName } from './types';
+
+export const frameworkName: SupportedFrameworkName = 'sveltekit';
+
+export const serve = (
+  options: ServeHandlerOptions
+): ((event: RequestEvent) => Promise<Response>) & {
+  GET: (event: RequestEvent) => Promise<Response>;
+  POST: (event: RequestEvent) => Promise<Response>;
+  PUT: (event: RequestEvent) => Promise<Response>;
+} => {
+  const handler = new EchoRequestHandler({
+    frameworkName,
+    ...options,
+    handler: (reqMethod: 'GET' | 'POST' | 'PUT' | undefined, event: RequestEvent) => {
+      return {
+        method: () => reqMethod || event.request.method || '',
+        body: () => event.request.json(),
+        headers: (key) => event.request.headers.get(key),
+        url: () => {
+          const protocol = process.env.NODE_ENV === 'development' ? 'http' : 'https';
+
+          return new URL(event.request.url, `${protocol}://${event.request.headers.get('host') || ''}`);
+        },
+        transformResponse: ({ body, headers, status }) => {
+          // Handle Response polyfills
+          // eslint-disable-next-line @typescript-eslint/naming-convention
+          let Res: typeof Response;
+
+          if (typeof Response === 'undefined') {
+            // eslint-disable-next-line @typescript-eslint/no-unsafe-assignment, @typescript-eslint/no-unsafe-member-access, @typescript-eslint/no-var-requires
+            Res = require('cross-fetch').Response;
+          } else {
+            // eslint-disable-next-line @typescript-eslint/no-unsafe-assignment
+            Res = Response;
+          }
+
+          return new Res(body, { status, headers });
+        },
+      };
+    },
+  });
+
+  const baseFn = handler.createHandler();
+
+  const fn = baseFn.bind(null, undefined);
+  type Fn = typeof fn;
+
+  const handlerFn = Object.defineProperties(fn, {
+    GET: { value: baseFn.bind(null, 'GET') },
+    POST: { value: baseFn.bind(null, 'POST') },
+    PUT: { value: baseFn.bind(null, 'PUT') },
+  }) as Fn & {
+    GET: Fn;
+    POST: Fn;
+    PUT: Fn;
+  };
+
+  return handlerFn;
+};

packages/echo/src/types/framework.types.ts

@@ -1 +1 @@
-export type SupportedFrameworkName = 'next' | 'express' | 'nuxt' | 'h3';
+export type SupportedFrameworkName = 'next' | 'express' | 'nuxt' | 'h3' | 'sveltekit';

packages/echo/tsup.config.ts

@@ -1,7 +1,7 @@
 import { defineConfig } from 'tsup';
 import { type SupportedFrameworkName } from './src';
 
-const frameworks: SupportedFrameworkName[] = ['h3', 'express', 'next', 'nuxt'];
+const frameworks: SupportedFrameworkName[] = ['h3', 'express', 'next', 'nuxt', 'sveltekit'];
 
 export default defineConfig({
   entry: ['src/index.ts', ...frameworks.map((framework) => `src/${framework}.ts`)],