Adding isAxiosError flag to errors thrown by axios

index.d.ts

@@ -81,6 +81,7 @@ export interface AxiosError extends Error {
   code?: string;
   request?: any;
   response?: AxiosResponse;
+  isAxiosError: boolean;
 }
 
 export interface AxiosPromise<T = any> extends Promise<AxiosResponse<T>> {

lib/core/enhanceError.js

@@ -15,8 +15,11 @@ module.exports = function enhanceError(error, config, code, request, response) {
   if (code) {
     error.code = code;
   }
+
   error.request = request;
   error.response = response;
+  error.isAxiosError = true;
+
   error.toJSON = function() {
     return {
       // Standard

test/specs/core/createError.spec.js

@@ -1,7 +1,7 @@
 var createError = require('../../../lib/core/createError');
 
 describe('core::createError', function() {
-  it('should create an Error with message, config, code, request and response', function() {
+  it('should create an Error with message, config, code, request, response and isAxiosError', function() {
     var request = { path: '/foo' };
     var response = { status: 200, data: { foo: 'bar' } };
     var error = createError('Boom!', { foo: 'bar' }, 'ESOMETHING', request, response);
@@ -11,6 +11,7 @@ describe('core::createError', function() {
     expect(error.code).toBe('ESOMETHING');
     expect(error.request).toBe(request);
     expect(error.response).toBe(response);
+    expect(error.isAxiosError).toBe(true);
   });
   it('should create an Error that can be serialized to JSON', function() {
     // Attempting to serialize request and response results in

test/specs/core/enhanceError.spec.js

@@ -11,6 +11,7 @@ describe('core::enhanceError', function() {
     expect(error.code).toBe('ESOMETHING');
     expect(error.request).toBe(request);
     expect(error.response).toBe(response);
+    expect(error.isAxiosError).toBe(true);
   });
 
   it('should return error', function() {