fix: preserve original error when API error body has no error.type

src/lib/utils.ts

@@ -128,13 +128,12 @@ export function canRaiseHTTPError(
     try {
       return await descriptor.value.apply(this, args);
     } catch (exc: any) {
-      if (axios.isAxiosError(exc) && exc.response) {
-        const errorData = exc.response.data as Record<string, any>;
-        const ErrorKlass = getErrorClass(errorData.error.type);
-        throw new ErrorKlass(errorData.error);
-      } else {
-        throw exc;
+      const apiError = axios.isAxiosError(exc) ? exc.response?.data?.error : undefined;
+      if (apiError && typeof apiError === 'object' && typeof apiError.type === 'string') {
+        const ErrorKlass = getErrorClass(apiError.type);
+        throw new ErrorKlass(apiError);
       }
+      throw exc;
     }
   };
 

src/spec/utils/canRaiseHTTPError.spec.ts

@@ -1,6 +1,6 @@
 import test from 'ava';
 
-import { FintocError } from '../../lib/errors';
+import { FintocError, InvalidRequestError } from '../../lib/errors';
 import { canRaiseHTTPError } from '../../lib/utils';
 
 class Errors {
@@ -28,6 +28,20 @@ class Errors {
   throwGenericError() {
     throw new Error();
   }
+
+  @canRaiseHTTPError
+  throwAxiosError(error: Error) {
+    throw error;
+  }
+}
+
+function buildAxiosError(data: unknown) {
+  const error = new Error('Request failed with status code 400');
+  // @ts-ignore: property does not exist
+  error.isAxiosError = true;
+  // @ts-ignore: property does not exist
+  error.response = { status: 400, data };
+  return error;
 }
 
 test.beforeEach((t) => {
@@ -53,3 +67,35 @@ test('"canRaiseHTTPError" generic error', async (t) => {
 
   await t.throwsAsync(ctx.errors.throwGenericError, { instanceOf: Error });
 });
+
+test('"canRaiseHTTPError" typed API error body', async (t) => {
+  const ctx: any = t.context;
+  const original = buildAxiosError({
+    error: { type: 'invalid_request_error', message: 'Bad param' },
+  });
+
+  await t.throwsAsync(() => ctx.errors.throwAxiosError(original), {
+    instanceOf: InvalidRequestError,
+  });
+});
+
+const bodiesWithoutErrorType: [string, unknown][] = [
+  ['string body', '400 Bad Request'],
+  ['HTML body', '<html><body><h1>400 Bad Request</h1></body></html>'],
+  ['empty object body', {}],
+  ['object body without error.type', { error: {} }],
+  ['non-object error', { error: 'Bad Request' }],
+  ['undefined body', undefined],
+  ['null body', null],
+];
+
+bodiesWithoutErrorType.forEach(([description, data]) => {
+  test(`"canRaiseHTTPError" re-throws the original error with ${description}`, async (t) => {
+    const ctx: any = t.context;
+    const original = buildAxiosError(data);
+
+    const thrown = await t.throwsAsync(() => ctx.errors.throwAxiosError(original));
+
+    t.is(thrown, original);
+  });
+});