fix(typescript-fetch): ResponseError prototype chain

Author: jehiah

modules/openapi-generator/src/main/resources/typescript-fetch/runtime.mustache

@@ -251,20 +251,44 @@ export class ResponseError extends Error {
     override name: "ResponseError" = "ResponseError";
     constructor(public response: Response, msg?: string) {
         super(msg);
+
+        // restore prototype chain
+        const actualProto = new.target.prototype;
+        if (Object.setPrototypeOf) {
+            Object.setPrototypeOf(this, actualProto);
+        } else {
+            this.__proto__ = actualProto;
+        }
     }
 }
 
 export class FetchError extends Error {
     override name: "FetchError" = "FetchError";
     constructor(public cause: Error, msg?: string) {
         super(msg);
+
+        // restore prototype chain
+        const actualProto = new.target.prototype;
+        if (Object.setPrototypeOf) {
+            Object.setPrototypeOf(this, actualProto);
+        } else {
+            this.__proto__ = actualProto;
+        }
     }
 }
 
 export class RequiredError extends Error {
     override name: "RequiredError" = "RequiredError";
     constructor(public field: string, msg?: string) {
         super(msg);
+
+        // restore prototype chain
+        const actualProto = new.target.prototype;
+        if (Object.setPrototypeOf) {
+            Object.setPrototypeOf(this, actualProto);
+        } else {
+            this.__proto__ = actualProto;
+        }
     }
 }
 

samples/client/petstore/typescript-fetch/tests/default/test/PetApi.ts

@@ -1,5 +1,5 @@
 import { expect } from 'chai';
-import { PetApi, Pet, PetStatusEnum, Category } from '@swagger/typescript-fetch-petstore';
+import { PetApi, Pet, PetStatusEnum, Category, ResponseError } from '@swagger/typescript-fetch-petstore';
 import { config } from '../configuration';
 
 describe('PetApi', () => {
@@ -49,6 +49,13 @@ describe('PetApi', () => {
                 });
             });
 
+            it('instanceof ResponseError not Error', () => {
+                const response = new Response();
+                const err = new ResponseError(response, 'test error message');
+                expect(err instanceof ResponseError).to.be.true;
+                expect(err instanceof Error).to.be.false;
+            });
+
         });
     }