fix: allow route handlers to return plain objects as JSON responses

src/create-with-winter-spec.ts

@@ -198,6 +198,18 @@ function serializeToResponse(
     throw new Error("Unknown Response type")
   }
 
+  // Allow routes to return a plain object instead of WinterSpecJsonResponse.
+  // e.g. `return { ok: true }` is equivalent to `return new WinterSpecJsonResponse({ ok: true })`.
+  if (
+    response !== null &&
+    typeof response === "object" &&
+    !(response instanceof Response)
+  ) {
+    return new WinterSpecJsonResponse(response as any).serializeToResponse(
+      routeSpec.jsonResponse ?? z.any()
+    )
+  }
+
   return response
 }
 

tests/endpoints/plain-object-return.test.ts

@@ -0,0 +1,77 @@
+import test from "ava"
+import { z } from "zod"
+import { getTestRoute } from "../fixtures/get-test-route.js"
+
+test("plain-object-return: GET route returning plain object is serialized as JSON", async (t) => {
+  const { axios } = await getTestRoute(t, {
+    globalSpec: {
+      apiName: "hello-world",
+      productionServerUrl: "https://example.com",
+      authMiddleware: {},
+      beforeAuthMiddleware: [],
+    },
+    routeSpec: {
+      auth: "none",
+      methods: ["GET"],
+    },
+    routePath: "/health",
+    routeFn: async (_req: any): Promise<any> => {
+      return { ok: true }
+    },
+  })
+
+  const { data, status } = await axios.get("/health")
+  t.is(status, 200)
+  t.is(data.ok, true)
+})
+
+test("plain-object-return: POST route returning plain object with multiple fields", async (t) => {
+  const { axios } = await getTestRoute(t, {
+    globalSpec: {
+      apiName: "hello-world",
+      productionServerUrl: "https://example.com",
+      authMiddleware: {},
+      beforeAuthMiddleware: [],
+    },
+    routeSpec: {
+      auth: "none",
+      methods: ["POST"],
+      jsonResponse: z.object({
+        message: z.string(),
+        count: z.number(),
+      }),
+    },
+    routePath: "/items",
+    routeFn: async (_req: any): Promise<any> => {
+      return { message: "created", count: 42 }
+    },
+  })
+
+  const { data, status } = await axios.post("/items")
+  t.is(status, 200)
+  t.is(data.message, "created")
+  t.is(data.count, 42)
+})
+
+test("plain-object-return: plain object validates against jsonResponse schema", async (t) => {
+  const { axios } = await getTestRoute(t, {
+    globalSpec: {
+      apiName: "hello-world",
+      productionServerUrl: "https://example.com",
+      authMiddleware: {},
+      beforeAuthMiddleware: [],
+    },
+    routeSpec: {
+      auth: "none",
+      methods: ["GET"],
+      jsonResponse: z.object({ ok: z.boolean() }),
+    },
+    routePath: "/check",
+    routeFn: async (_req: any): Promise<any> => {
+      return { ok: true }
+    },
+  })
+
+  const { data } = await axios.get("/check")
+  t.is(data.ok, true)
+})