fix: swallowed exceptions from improper exports

Adapters were causing multiple instances of OAuthExceptions to be created, one for each instance.
Instead of going down the bundler rabbit hole, I was thinking about how to fix this, and I realized
that the simplest way is to add a marker on the OAuthException (OAuthException.oauth) and check for
it instead of using instance of. Resolves #82

#82 (comment)

src/adapters/express.ts

@@ -3,6 +3,7 @@ import { OAuthException } from "../exceptions/oauth.exception.js";
 
 import { OAuthRequest } from "../requests/request.js";
 import { OAuthResponse } from "../responses/response.js";
+import { isOAuthError } from "../utils/errors.js";
 
 export function responseFromExpress(res: Response): OAuthResponse {
   return new OAuthResponse(res);
@@ -25,7 +26,7 @@ export function handleExpressResponse(expressResponse: Response, oauthResponse:
 
 // @todo v4.0 flip these to always be Express as first arg, OAuth as second. Then update Docs
 export function handleExpressError(e: unknown | OAuthException, res: Response): void {
-  if (e instanceof OAuthException) {
+  if (isOAuthError(e)) {
     res.status(e.status);
     res.send({
       status: e.status,

src/adapters/fastify.ts

@@ -3,6 +3,7 @@ import { OAuthException } from "../exceptions/oauth.exception.js";
 
 import { OAuthRequest } from "../requests/request.js";
 import { OAuthResponse } from "../responses/response.js";
+import { isOAuthError } from "../utils/errors.js";
 
 export function responseFromFastify(res: FastifyReply): OAuthResponse {
   return new OAuthResponse({
@@ -20,7 +21,7 @@ export function requestFromFastify(req: FastifyRequest): OAuthRequest {
 
 // @todo v4.0 flip these to always be Fastify as first arg, OAuth as second. Then update Docs
 export function handleFastifyError(e: unknown | OAuthException, res: FastifyReply): void {
-  if (e instanceof OAuthException) {
+  if (isOAuthError(e)) {
     res.status(e.status).send({
       status: e.status,
       message: e.message,

src/exceptions/oauth.exception.ts

@@ -18,6 +18,8 @@ export enum ErrorType {
 }
 
 export class OAuthException extends Error {
+  private readonly oauth = true;
+
   constructor(
     public readonly error: string,
     public readonly errorType: ErrorType,
@@ -123,4 +125,8 @@ export class OAuthException extends Error {
       HttpStatus.INTERNAL_SERVER_ERROR,
     );
   }
+
+  get isOAuth(): boolean {
+    return this.oauth;
+  }
 }

src/utils/errors.ts

@@ -0,0 +1,7 @@
+import { OAuthException } from "../exceptions/oauth.exception.js";
+
+export function isOAuthError(error: unknown): error is OAuthException {
+  if (!error) return false;
+  if (typeof error !== "object") return false;
+  return "oauth" in error;
+}

test/e2e/adapters/fastify.spec.ts

@@ -0,0 +1,59 @@
+import { describe, it, expect, vi } from "vitest";
+import { FastifyReply, FastifyRequest } from "fastify";
+import { handleFastifyError, requestFromFastify, responseFromFastify } from "../../../src/adapters/fastify.js";
+import { ErrorType, OAuthException, OAuthRequest, OAuthResponse } from "../../../src/index.js";
+
+describe("Fastify OAuth Utilities", () => {
+  describe("responseFromFastify", () => {
+    it("should create an OAuthResponse from FastifyReply", () => {
+      const mockReply = {
+        headers: { "Content-Type": "application/json" },
+      } as unknown as FastifyReply;
+
+      const result = responseFromFastify(mockReply);
+      expect(result).toBeInstanceOf(OAuthResponse);
+      expect(result.headers).toEqual({ "Content-Type": "application/json" });
+    });
+  });
+
+  describe("requestFromFastify", () => {
+    it("should create an OAuthRequest from FastifyRequest", () => {
+      const mockRequest = {
+        query: { code: "abc123" },
+        body: { grant_type: "authorization_code" },
+        headers: { "Content-Type": "application/json" },
+      } as unknown as FastifyRequest;
+
+      const result = requestFromFastify(mockRequest);
+      expect(result).toBeInstanceOf(OAuthRequest);
+      expect(result.query).toEqual({ code: "abc123" });
+      expect(result.body).toEqual({ grant_type: "authorization_code" });
+      expect(result.headers).toEqual({ "Content-Type": "application/json" });
+    });
+  });
+
+  describe("handleFastifyError", () => {
+    it("should handle OAuthException", () => {
+      const mockReply = {
+        status: vi.fn().mockReturnThis(),
+        send: vi.fn(),
+      } as unknown as FastifyReply;
+
+      const oauthError = new OAuthException("Test error", ErrorType.InternalServerError);
+      handleFastifyError(oauthError, mockReply);
+
+      expect(mockReply.status).toHaveBeenCalledWith(400);
+      expect(mockReply.send).toHaveBeenCalledWith({
+        status: 400,
+        message: "Test error",
+      });
+    });
+
+    it("should throw non-OAuthException errors", () => {
+      const mockReply = {} as FastifyReply;
+      const error = new Error("Regular error");
+
+      expect(() => handleFastifyError(error, mockReply)).toThrow("Regular error");
+    });
+  });
+});

vitest.config.ts

@@ -8,6 +8,6 @@ export default defineConfig({
       exclude: [".github/**", ".idea/**", "docs/**", "example/**"],
     },
     setupFiles: ["test/setup.ts"],
-    exclude: ["node_modules/**", "example/**", "version-check.ts"],
+    exclude: ["docs/**", "example/**", "node_modules/**", "version-check.ts"],
   },
 });