feat: support for @example and @pattern tags in schema properties

Author: Ansh Chaturvedi

packages/openapi-generator/src/openapi.ts

@@ -15,9 +15,13 @@ function schemaToOpenAPI(
     schema: Schema,
   ): OpenAPIV3.SchemaObject | OpenAPIV3.ReferenceObject | undefined => {
     const description = schema.comment?.description;
+    const example = getTagName(schema, 'example');
+    const pattern = getTagName(schema, 'pattern');
 
-    const defaultObject = {
+    const defaultOpenAPIObject = {
       ...(description ? { description } : {}),
+      ...(example ? { example } : {}),
+      ...(pattern ? { pattern } : {}),
     };
 
     switch (schema.type) {
@@ -27,13 +31,13 @@ function schemaToOpenAPI(
         return {
           type: schema.type,
           ...(schema.enum ? { enum: schema.enum } : {}),
-          ...defaultObject,
+          ...defaultOpenAPIObject,
         };
       case 'integer':
         return {
           type: 'number',
           ...(schema.enum ? { enum: schema.enum } : {}),
-          ...defaultObject,
+          ...defaultOpenAPIObject,
         };
       case 'null':
         // TODO: OpenAPI v3 does not have an explicit null type, is there a better way to represent this?
@@ -46,11 +50,11 @@ function schemaToOpenAPI(
         if (innerSchema === undefined) {
           return undefined;
         }
-        return { type: 'array', items: innerSchema, ...defaultObject };
+        return { type: 'array', items: innerSchema, ...defaultOpenAPIObject };
       case 'object':
         return {
           type: 'object',
-          ...defaultObject,
+          ...defaultOpenAPIObject,
           properties: Object.entries(schema.properties).reduce(
             (acc, [name, prop]) => {
               const innerSchema = schemaToOpenAPI(prop);
@@ -73,7 +77,7 @@ function schemaToOpenAPI(
             }
             return [innerSchema];
           }),
-          ...defaultObject,
+          ...defaultOpenAPIObject,
         };
       case 'union':
         let nullable = false;
@@ -100,12 +104,16 @@ function schemaToOpenAPI(
             return {
               ...(nullable ? { nullable } : {}),
               allOf: oneOf,
-              ...defaultObject,
+              ...defaultOpenAPIObject,
             };
           else
-            return { ...(nullable ? { nullable } : {}), ...oneOf[0], ...defaultObject };
+            return {
+              ...(nullable ? { nullable } : {}),
+              ...oneOf[0],
+              ...defaultOpenAPIObject,
+            };
         } else {
-          return { ...(nullable ? { nullable } : {}), oneOf, ...defaultObject };
+          return { ...(nullable ? { nullable } : {}), oneOf, ...defaultOpenAPIObject };
         }
       case 'record':
         const additionalProperties = schemaToOpenAPI(schema.codomain);
@@ -115,7 +123,7 @@ function schemaToOpenAPI(
         return {
           type: 'object',
           additionalProperties,
-          ...defaultObject,
+          ...defaultOpenAPIObject,
         };
       case 'undefined':
         return undefined;
@@ -140,6 +148,10 @@ function schemaToOpenAPI(
   return openAPIObject;
 }
 
+function getTagName(schema: Schema, tagName: String): string | undefined {
+  return schema.comment?.tags.find((t) => t.tag === tagName)?.name;
+}
+
 function routeToOpenAPI(route: Route): [string, string, OpenAPIV3.OperationObject] {
   const jsdoc = route.comment !== undefined ? parseCommentBlock(route.comment) : {};
   const operationId = jsdoc.tags?.operationId;

packages/openapi-generator/test/openapi.test.ts

@@ -2036,3 +2036,146 @@ testCase('route with record types and descriptions', ROUTE_WITH_RECORD_TYPES_AND
     schemas: {}
   }
 });
+
+const ROUTE_WITH_DESCRIPTIONS_PATTERNS_EXAMPLES = `
+import * as t from 'io-ts';
+import * as h from '@api-ts/io-ts-http';
+
+/**
+ * A simple route with type descriptions
+ *
+ * @operationId api.v1.test
+ * @tag Test Routes
+ */
+export const route = h.httpRoute({
+  path: '/foo',
+  method: 'GET',
+  request: h.httpRequest({
+    query: {
+      /** 
+       * This is a bar param.
+       * @example { "foo": "bar" }
+      */
+      bar: t.record(t.string, t.string),
+    },
+    body: {
+      /**
+       * foo description
+       * @pattern ^[1-9][0-9]{4}$
+       * @example 12345
+      */
+      foo: t.number,
+      child: {
+        /** 
+         * child description 
+        */
+        child: t.array(t.union([t.string, t.number])),
+      }
+    },
+  }),
+  response: {
+    200: {
+      test: t.string
+    }
+  },
+});
+`;
+
+testCase('route with descriptions, patterns, and examples', ROUTE_WITH_DESCRIPTIONS_PATTERNS_EXAMPLES, {
+  openapi: '3.0.3',
+  info: {
+    title: 'Test',
+    version: '1.0.0'
+  },
+  paths: {
+    '/foo': {
+      get: {
+        summary: 'A simple route with type descriptions',
+        operationId: 'api.v1.test',
+        tags: [
+          'Test Routes'
+        ],
+        parameters: [
+          {
+            name: 'bar',
+            description: 'This is a bar param.',
+            in: 'query',
+            required: true,
+            schema: {
+              type: 'object',
+              additionalProperties: {
+                type: 'string'
+              }
+            }
+          }
+        ],
+        requestBody: {
+          content: {
+            'application/json': {
+              schema: {
+                type: 'object',
+                properties: {
+                  foo: {
+                    type: 'number',
+                    description: 'foo description',
+                    example: '12345',
+                    pattern: '^[1-9][0-9]{4}$'
+                  },
+                  child: {
+                    type: 'object',
+                    properties: {
+                      child: {
+                        type: 'array',
+                        items: {
+                          oneOf: [
+                            {
+                              type: 'string'
+                            },
+                            {
+                              type: 'number'
+                            }
+                          ]
+                        },
+                        description: 'child description'
+                      }
+                    },
+                    required: [
+                      'child'
+                    ]
+                  }
+                },
+                required: [
+                  'foo',
+                  'child'
+                ]
+              }
+            }
+          }
+        },
+        responses: {
+          '200': {
+            description: 'OK',
+            content: {
+              'application/json': {
+                schema: {
+                  type: 'object',
+                  properties: {
+                    test: {
+                      type: 'string'
+                    }
+                  },
+                  required: [
+                    'test'
+                  ]
+                }
+              }
+            }
+          }
+        }
+      }
+    }
+  },
+  components: {
+    schemas: {}
+  }
+});