error.response.data is undefined when using axios interceptors.request

Question

I'm using "axios": "^0.18.0"

I am intercepting requests and responses and I'm adding token when intercepting requests.

when I use request interceptor then in response interceptor if I get [400,...] error my "error.response.data" is undefined and I don't have access to exception types and messages to translate them

when I remove request interceptor it works correctly but I need request interceptor to add token

axiosAuthInstance.interceptors.request.use((config)=>{
    console.log('Auth req config=>', config.url);
    console.log('auth req ',config);

    const token = store.getState().tokenReducer.access_token;
    console.log(token);
    if (token != null || token !== '.') {
        config.headers.Authorization = `Bearer ${token}`;
        console.log('authed');
    }
    return config;
},(error)=>{
    ToastMaker().withoutAction('Ooops Error in Auth Request Interceptor','warning');
    console.log(error);
    return Promise.reject(error);
});
//------------------------------------------
axiosAuthInstance.interceptors.response.use((response)=>{
    console.log('Auth resp response=>',response);
    if (response.data.error) {
        console.log('hereeeeeee !!!');
        // return Promise.reject(response);
    }
    return response;
},(error)=>{
    switch(error.response.status){
        case 400:{
            console.log(error.response.data.customExceptionDetailModelList);
            error.response.data.customExceptionDetailModelList.forEach((item)=>{console.log(item.message.error)});
            ToastMaker().withoutAction(`${error.response.status}` + " "+error.response.data.error_description,'warning');
            break;
        }

        case 401:{
            console.log('shafffft');
            console.log(error.response.data.customExceptionDetailModelList);
            error.response.data.customExceptionDetailModelList.forEach((item)=>{console.log(item.message.error)});
            ToastMaker().withoutAction(`${error.response.status}` +" "+error.response.data.error_description,'warning');
            break;
        }

        case 404:{
            console.log(error.response.data.customExceptionDetailModelList);
            error.response.data.customExceptionDetailModelList.forEach((item)=>{console.log(item.message.error)});
            ToastMaker().withoutAction(`${error.response.status}` + " "+error.response.data.error_description,'warning');
            break;
        }

        case 500:{
            ToastMaker().withoutAction(`${error.response.status}` +" "+error.response.data.error_description,'warning');
            break;
        }

        default:{
            ToastMaker().withoutAction('مشکل ارتباط با سرور','warning');
            break;
        }
    }
    console.log(error.response);
    return Promise.reject(error);
});

this is how it works without request.intercept

and here is what it looks like after using request interceptor

Answer 1

In my experience, error.response is not defined when the server (for some reasons) fails to respond (e.g. Timeout). Therefore you don't get any status code nor error message.

I usually cope with both the situations:

axios.interceptors.response.use(response => {
  return response
}, error => {
  if (!error.response) {
    // Show a generic error Toast (e.g. Server error, please retry)
    return
  }

  const { response: { status } } = error
  if (status === 401) {
    // Refresh token
  }
  return Promise.reject(error)
})