feat(apigateway): default value for enum type in schema models (#11064)

Fixes: #11065
Add default to JsonSchema


----

*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

packages/@aws-cdk/aws-apigateway/lib/json-schema.ts

@@ -35,6 +35,12 @@ export interface JsonSchema {
   readonly title?: string;
   readonly description?: string;
   readonly 'enum'?: any[];
+  /**
+   * The default value if you use an enum.
+   *
+   * @default - not set
+   */
+  readonly default?: any;
   readonly format?: string;
   readonly definitions?: { [name: string]: JsonSchema };
 

packages/@aws-cdk/aws-apigateway/test/util.test.ts

@@ -121,5 +121,21 @@ describe('util', () => {
         required: ['ref'],
       });
     });
+
+    test('"default" for enum', () => {
+      const schema: JsonSchema = {
+        type: JsonSchemaType.STRING,
+        enum: ['green', 'blue', 'red'],
+        default: 'blue',
+      };
+
+      const actual = JsonSchemaMapper.toCfnJsonSchema(schema);
+      expect(actual).toEqual({
+        $schema: 'http://json-schema.org/draft-04/schema#',
+        type: 'string',
+        enum: ['green', 'blue', 'red'],
+        default: 'blue',
+      });
+    });
   });
 });