Default values supporting scalar and object

.chronus/changes/almend-ScalarDefaultValue-2024-8-12-15-34-32.md

@@ -0,0 +1,7 @@
+---
+changeKind: feature
+packages:
+  - "@typespec/openapi3"
+---
+
+Added support to use Scalar and Object as default types

packages/openapi3/src/schema-emitter.ts

@@ -936,10 +936,14 @@ export function getDefaultValue(program: Program, defaultType: Value): any {
       return null;
     case "EnumValue":
       return defaultType.value.value ?? defaultType.value.name;
+    case "ScalarValue":
+      return serializeValueAsJson(program, defaultType, defaultType.type);
+    case "ObjectValue":
+      return serializeValueAsJson(program, defaultType, defaultType.type);
     default:
       reportDiagnostic(program, {
         code: "invalid-default",
-        format: { type: defaultType.valueKind },
+        format: { type: defaultType },
         target: defaultType,
       });
   }

packages/openapi3/test/primitive-types.test.ts

@@ -1,5 +1,5 @@
 import { deepStrictEqual, ok, strictEqual } from "assert";
-import { describe, it } from "vitest";
+import { describe, expect, it } from "vitest";
 import { OpenAPI3Schema } from "../src/types.js";
 import { oapiForModel, openApiFor } from "./test-host.js";
 
@@ -115,6 +115,43 @@ describe("openapi3: primitives", () => {
       });
     });
 
+    it("scalar used as a default value", async () => {
+      const res = await oapiForModel(
+        "Pet",
+        `
+      scalar shortName { init name(value: string);}
+
+      model Pet { name: shortName = shortName.name("Shorty"); }
+      `
+      );
+
+      expect(res.schemas.Pet.properties.name.default).toEqual("Shorty");
+    });
+
+    it("known scalar used as a default value", async () => {
+      const res = await oapiForModel(
+        "Test",
+        `
+      model Test { minDate: utcDateTime = utcDateTime.fromISO("2024-01-2T3:04:05Z"); }
+        `
+      );
+
+      expect(res.schemas.Test.properties.minDate.default).toEqual("2024-01-2T3:04:05Z");
+      expect(res.schemas.Test.properties.minDate.format).toEqual("date-time");
+      expect(res.schemas.Test.properties.minDate.type).toEqual("string");
+    });
+
+    it("object value used as a default value", async () => {
+      const res = await oapiForModel(
+        "Test",
+        `
+      model Test { Pet: {name: string;} = #{ name: "Dog"}; }
+      `
+      );
+
+      expect(res.schemas.Test.properties.Pet.default.name).toEqual("Dog");
+    });
+
     it("merge the data from parent", async () => {
       const res = await oapiForModel(
         "Pet",