From 1b19590c9933ac6a4c129337d6988d724589bb54 Mon Sep 17 00:00:00 2001
From: Evert De Spiegeleer <evert.despiegeleer@rightcrowd.com>
Date: Sun, 7 Jan 2024 20:51:13 +0100
Subject: [PATCH] =?UTF-8?q?feat:=20=E2=9C=A8=20allow=20non-async=20handler?=
 =?UTF-8?q?s=20on=20endpoints?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
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---
 src/util/endpoint.ts           | 17 +++++++++++------
 src/util/endpoint.unit.test.ts |  2 +-
 2 files changed, 12 insertions(+), 7 deletions(-)

diff --git a/src/util/endpoint.ts b/src/util/endpoint.ts
index 3094a56..0b4e62f 100644
--- a/src/util/endpoint.ts
+++ b/src/util/endpoint.ts
@@ -4,6 +4,7 @@ import type { NextFunction, Request, Response } from 'express'
 import { type Middleware } from './middleware.js'
 import { type EndpointOasInfo } from '../oas.js'
 import { NotImplementedError, ValidationError } from './errors.js'
+import { isPromise } from 'util/types'
 
 const methods = [
   'get',
@@ -51,7 +52,7 @@ export interface EndpointOptions<
     inputs: z.infer<InputsSchema>,
     req: Request,
     res: Response,
-  ) => Promise<z.infer<OutputSchema>>
+  ) => Promise<z.infer<OutputSchema>> | z.infer<OutputSchema>
   inputValidationSchema?: InputsSchema
   responseValidationSchema?: OutputSchema
   responseContentType: string
@@ -267,14 +268,18 @@ export const endpointToExpressHandler = (endpoint: AnyEndpoint) => {
 
     const { params, query, body } = req
 
-    if (endpoint.getHandler() == null) {
+    const handler = endpoint.getHandler()
+
+    if (handler == null) {
       next(new NotImplementedError())
       return
     }
 
-    endpoint
-      .getHandler()?.({ params, query, body }, req, res)
-      .then((responseObj) => {
+    // Turn any hanler, async or not, into an async handler
+    const asyncHandler = isPromise(handler) ? handler : async (input: Parameters<typeof handler>[0], req: Parameters<typeof handler>[1], res: Parameters<typeof handler>[2]): Promise<ReturnType<typeof handler>> => handler(input, req, res)
+
+    asyncHandler({ params, query, body }, req, res)
+      .then((responseObj: any) => {
         // Output validation
         try {
           endpoint.getResponseValidationSchema()?.parse(responseObj)
@@ -287,7 +292,7 @@ export const endpointToExpressHandler = (endpoint: AnyEndpoint) => {
         res.header('content-type', endpoint.getResponseContentType())
         res.send(responseObj)
       })
-      .catch((e) => {
+      .catch((e: any) => {
         next(e)
       })
   }
diff --git a/src/util/endpoint.unit.test.ts b/src/util/endpoint.unit.test.ts
index 264a6a0..be45548 100644
--- a/src/util/endpoint.unit.test.ts
+++ b/src/util/endpoint.unit.test.ts
@@ -57,7 +57,7 @@ describe('endpoint', () => {
         })
       )
       .response(zApiOutput(z.string()))
-      .handler(async ({ query }) => {
+      .handler(({ query }) => {
         return apiResponse(`Hello ${query.name ?? 'everyone'}!`)
       })
   })