chore: apiSpec may be const literal (#854)

Co-authored-by: Carmine DiMascio <[email protected]>

Author: duncanbeevers

src/framework/types.ts

@@ -113,8 +113,26 @@ export type SerDesMap = {
   [format: string]: SerDes
 };
 
+type Primitive = undefined | null | boolean | string | number | Function
+
+type Immutable<T> =
+  T extends Primitive ? T :
+    T extends Array<infer U> ? ReadonlyArray<U> :
+      T extends Map<infer K, infer V> ? ReadonlyMap<K, V> : Readonly<T>
+
+type DeepImmutable<T> =
+  T extends Primitive ? T :
+    T extends Array<infer U> ? DeepImmutableArray<U> :
+      T extends Map<infer K, infer V> ? DeepImmutableMap<K, V> : DeepImmutableObject<T>
+
+interface DeepImmutableArray<T> extends ReadonlyArray<DeepImmutable<T>> {}
+interface DeepImmutableMap<K, V> extends ReadonlyMap<DeepImmutable<K>, DeepImmutable<V>> {}
+type DeepImmutableObject<T> = {
+  readonly [K in keyof T]: DeepImmutable<T[K]>
+}
+
 export interface OpenApiValidatorOpts {
-  apiSpec: OpenAPIV3.Document | string;
+  apiSpec: DeepImmutable<OpenAPIV3.Document> | string;
   validateApiSpec?: boolean;
   validateResponses?: boolean | ValidateResponseOpts;
   validateRequests?: boolean | ValidateRequestOpts;

test/default-export.spec.ts

@@ -4,27 +4,29 @@ import { expect } from 'chai';
 import * as request from 'supertest';
 import * as path from 'path';
 
+const schema = {
+  openapi: '3.0.0',
+  info: { version: '1.0.0', title: 'test bug OpenApiValidator' },
+  servers: [],
+  paths: {
+    '/': {
+      get: {
+        operationId: 'anything',
+        'x-eov-operation-handler': 'controller-with-default',
+        responses: { 200: { description: 'home api' } }
+      }
+    },
+  },
+} as const;
+
 describe('default export resolver', () => {
   let server = null;
   let app = express();
 
   before(async () => {
     app.use(
       OpenApiValidator.middleware({
-        apiSpec: {
-          openapi: '3.0.0',
-          info: { version: '1.0.0', title: 'test bug OpenApiValidator' },
-          paths: {
-            '/': {
-              get: {
-                operationId: 'anything',
-                // @ts-ignore
-                'x-eov-operation-handler': 'controller-with-default',
-                responses: { 200: { description: 'home api' } }
-              }
-            },
-          },
-        },
+        apiSpec: schema,
         operationHandlers: path.join(__dirname, 'resources'),
       }),
     );