How do I retrieve the error message from an API request

Question

I am building an authentication project. I am unsure on how to get the error messages to show up so that I can print them on the screen. For example, If the email address has already registered, how can I get that error. I am able to see the error message when I test with postman but I'm unsure how to do it with using axios. Below is the code for when a user enters an email thats already registered. How do I access that message

User.findOne({ email }).then(user => {
    if (user)
        return res.status(400).json({ msg: "Email already in use" });
});

score 4 · Answer 1 · answered Jul 11 '19 at 22:25

What's happening is that when your server returns a status code (like 400), it ends up as an exception in the client code (where you're executing your request). There's a couple of different ways to handle this, but the easiest way to is to do a try/catch

Here's an example of what they suggest on their GitHub:

/*
 * Handling Errors using async/await
 * Has to be used inside an async function
 */
try {
    const response = await axios.get('https://your.site/api/v1/bla/ble/bli');
    // Success 
    console.log(response);
} catch (error) {
    // Error 
    if (error.response) {
        /*
         * The request was made and the server responded with a
         * status code that falls out of the range of 2xx
         */
        console.log(error.response.data);
        console.log(error.response.status);
        console.log(error.response.headers);
    } else if (error.request) {
        /*
         * The request was made but no response was received, `error.request`
         * is an instance of XMLHttpRequest in the browser and an instance
         * of http.ClientRequest in Node.js
         */
        console.log(error.request);
    } else {
        // Something happened in setting up the request and triggered an Error
        console.log('Error', error.message);
    }
    console.log(error);
}

They have some more examples here. In some other HttpClients, they have the option to always return a full http response. I don't see that option on Axios, but it might just be hidden in their documentation.

score 0 · Answer 2 · answered Jul 11 '19 at 22:29

Find more information on the axios documentation - https://github.com/axios/axios/blob/master/README.md

Assuming you have an api endpoint where you check the above criteria for unique email address, so with axios you can send post request to your endpoint and get the response back from the server. In the below example, replace httpbin url to your endpoint and execute to get the response.

You can access your msg and an error message will be posted in error log. Handle any exceptions in catch section.

console.log(response.msg)

axios.post('https://httpbin.org/post', {
    email: 'abc@xyz.com',
  })
  .then(function (response) {
    console.log(response);
  })
  .catch(function (error) {
    console.log(error);
  });

<script src="https://cdnjs.cloudflare.com/ajax/libs/axios/0.19.0/axios.js"></script>

How do I retrieve the error message from an API request

2 Answers2