React: Axios Network Error

This is my first time using axios and I have encountered an error.

  axios.get(
    `http://someurl.com/page1?param1=1&param2=${param2_id}`
  )
  .then(function(response) {
    alert();
  })
  .catch(function(error) {
    console.log(error);
  });

With the right url and parameters, when I check network requests I indeed get the right answer from my server, but when I open console I see that it didn't call the callback, but instead it caught an error.

Error: Network Error Stack trace: createError@http://localhost:3000/static/js/bundle.js:2188:15 handleError@http://localhost:3000/static/js/bundle.js:1717:14

If Creating an API Using NodeJS

// This should already be declared in your API file
var app = express();

// ADD THIS
var cors = require('cors');
app.use(cors());

For fuller understanding of CORS, please read the Mozilla Documentation on CORS.

my problem was about the url I was requesting to. I hadn't inserted http:// at the beginning of my url. I mean I was requesting to a url like 92.920.920.920/api/Token instead of http://92.920.920.920/api/Token. adding http:// solved my problem.

It happens when you work on localhost and forgot to add http://

Wrong Usage

  const headers = {
    "Content-Type": "application/json",
    Authorization: apiKey,
  };
  const url = "localhost:5000/api/expenses/get-expenses";

  axios.get(url, { headers });

  // NETWORK ERROR

The correct one is

  const headers = {
    "Content-Type": "application/json",
    Authorization: apiKey,
  };
  const url = "http://localhost:5000/api/expenses/get-expenses";

  axios.get(url, { headers });

  // WORKS FINE IF YOU HANDLED CORS CORRECTLY IN THE SERVER SIDE

In addition to @jacobhobson answer, I had also used some parameters to made it work.

app.use(cors({origin: true, credentials: true}));

I was having same issue on production on digital ocean droplet. I was using axios in ReactJS to call Node.js API.

Although I included cors

const cors = require('cors');
app.use(cors());

But I still had to add

res.header( "Access-Control-Allow-Origin" );

before calling out my controller. And it worked for me. There I realized that cors is not working properly. So I uninstalled and installed them again and It Works!

Complete code is here.

So either you use

 app.use(function(req, res, next) {
  res.header("Access-Control-Allow-Origin", "*");
  res.header('Access-Control-Allow-Methods', 'GET, POST, OPTIONS, PUT, PATCH, DELETE');
  res.header("Access-Control-Allow-Headers", "x-access-token, Origin, X-Requested-With, Content-Type, Accept");
  next();
});

or use

app.use(cors());

It's the same.