feat: support const in example generation (#1260)

Author: markrzen

packages/docusaurus-plugin-openapi-docs/src/openapi/createSchemaExample.test.ts

@@ -0,0 +1,57 @@
+/* ============================================================================
+ * Copyright (c) Palo Alto Networks
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ * ========================================================================== */
+
+import { sampleFromSchema } from "./createSchemaExample";
+import { SchemaObject } from "./types";
+
+describe("sampleFromSchema", () => {
+  describe("const support", () => {
+    it("should return default string value when const is not present", () => {
+      const schema: SchemaObject = {
+        type: "string",
+      };
+      const context = { type: "request" as const };
+
+      const result = sampleFromSchema(schema, context);
+
+      expect(result).toBe("string");
+    });
+
+    it("should return const value when const is present", () => {
+      const schema: SchemaObject = {
+        type: "string",
+        const: "example",
+      };
+      const context = { type: "request" as const };
+
+      const result = sampleFromSchema(schema, context);
+
+      expect(result).toBe("example");
+    });
+
+    it("should handle anyOf with const values", () => {
+      const schema: SchemaObject = {
+        type: "string",
+        anyOf: [
+          {
+            type: "string",
+            const: "dog",
+          },
+          {
+            type: "string",
+            const: "cat",
+          },
+        ],
+      };
+      const context = { type: "request" as const };
+
+      const result = sampleFromSchema(schema, context);
+
+      expect(result).toBe("dog");
+    });
+  });
+});

packages/docusaurus-plugin-openapi-docs/src/openapi/createSchemaExample.ts

@@ -111,7 +111,16 @@ export const sampleFromSchema = (
   try {
     // deep copy schema before processing
     let schemaCopy = JSON.parse(JSON.stringify(schema));
-    let { type, example, allOf, properties, items, oneOf, anyOf } = schemaCopy;
+    let {
+      type,
+      example,
+      allOf,
+      properties,
+      items,
+      oneOf,
+      anyOf,
+      const: constant,
+    } = schemaCopy;
 
     if (example !== undefined) {
       return example;
@@ -218,6 +227,10 @@ export const sampleFromSchema = (
       return undefined;
     }
 
+    if (constant) {
+      return constant;
+    }
+
     return primitive(schemaCopy);
   } catch (err) {
     console.error(