introduce payloadAsStream option type definitions #154

Author: adrai

package.json

@@ -46,6 +46,7 @@
     "@fastify/pre-commit": "^2.2.0",
     "@h4ad/serverless-adapter": "4.4.0",
     "@types/aws-lambda": "8.10.147",
+    "@types/node": "^22.10.7",
     "aws-serverless-express": "^3.4.0",
     "aws-serverless-fastify": "^3.1.0",
     "benchmark": "^2.1.4",

types/index.d.ts

@@ -1,5 +1,6 @@
 import { Context } from "aws-lambda";
 import { FastifyInstance, LightMyRequestResponse } from "fastify";
+import { Readable } from 'node:stream'
 
 type AwsLambdaFastify = typeof awsLambdaFastify
 
@@ -26,14 +27,23 @@ declare namespace awsLambdaFastify {
      * @default true
      */
     parseCommaSeparatedQueryParams?: boolean;
+    payloadAsStream?: boolean;
   }
 
-  export interface LambdaResponse {
+  export interface LambdaResponseBase {
     statusCode: number;
-    body: string;
     headers: Record<string, string>;
     isBase64Encoded: boolean;
-    cookies?: string[]
+    cookies?: string[];
+  }
+
+  export interface LambdaResponse extends LambdaResponseBase {
+    body: string;
+  }
+
+  export interface LambdaResponseStreamed {
+    meta: LambdaResponseBase;
+    stream: Readable;
   }
 
   export type PromiseHandler<TEvent = any, TResult = LambdaResponse> = (
@@ -51,14 +61,26 @@ declare namespace awsLambdaFastify {
   export { awsLambdaFastify as default }
 }
 
-declare function awsLambdaFastify<TEvent, TResult = awsLambdaFastify.LambdaResponse>(
+declare function awsLambdaFastify<
+  TEvent,
+  TOptions extends awsLambdaFastify.LambdaFastifyOptions = awsLambdaFastify.LambdaFastifyOptions,
+  TResult = TOptions["payloadAsStream"] extends true
+    ? awsLambdaFastify.LambdaResponseStreamed
+    : awsLambdaFastify.LambdaResponse
+>(
   app: FastifyInstance,
-  options?: awsLambdaFastify.LambdaFastifyOptions
+  options?: TOptions
 ): awsLambdaFastify.PromiseHandler<TEvent, TResult>;
 
-declare function awsLambdaFastify<TEvent, TResult = awsLambdaFastify.LambdaResponse>(
+declare function awsLambdaFastify<
+  TEvent,
+  TOptions extends awsLambdaFastify.LambdaFastifyOptions = awsLambdaFastify.LambdaFastifyOptions,
+  TResult = TOptions["payloadAsStream"] extends true
+    ? awsLambdaFastify.LambdaResponseStreamed
+    : awsLambdaFastify.LambdaResponse
+>(
   app: FastifyInstance,
-  options?: awsLambdaFastify.LambdaFastifyOptions
+  options?: TOptions
 ): awsLambdaFastify.CallbackHandler<TEvent, TResult>;
 
 export = awsLambdaFastify

types/index.test-d.ts

@@ -4,6 +4,7 @@ import awsLambdaFastify, {
   CallbackHandler,
   LambdaFastifyOptions,
   LambdaResponse,
+  LambdaResponseStreamed,
 } from "..";
 
 import { expectType, expectError, expectAssignable } from "tsd";
@@ -38,13 +39,17 @@ expectType<PromiseHandler<unknown>>(awsLambdaFastify(app));
 expectType<Promise<Record<string, string>>>(proxyPromise({}, lambdaCtx));
 expectType<PromiseHandler<unknown, LambdaResponse>>(awsLambdaFastify(app, {}));
 expectType<PromiseHandler<unknown, boolean>>(
-  awsLambdaFastify<unknown, boolean>(app)
+  awsLambdaFastify<unknown, {}, boolean>(app)
 );
 
 // Default type
 const proxyDefault = awsLambdaFastify(app);
 expectType<Promise<LambdaResponse>>(proxyDefault({}, lambdaCtx));
 
+// Streamed default type
+const proxyStreamed = awsLambdaFastify(app, { payloadAsStream: true });
+expectType<Promise<LambdaResponseStreamed>>(proxyStreamed({}, lambdaCtx));
+
 expectAssignable<LambdaFastifyOptions>({ binaryMimeTypes: ["foo", "bar"] });
 expectAssignable<LambdaFastifyOptions>({
   callbackWaitsForEmptyEventLoop: true,