Axios API is a bit different from the jQuery AJAX one. If you have to pass some params along with GET request, you need to use params property of config object (the second param of .get() method):

axios.get('/api/updatecart', {
  params: {
    product: this.product
  }
}).then(...)

You can pass either a plain object or a URLSearchParams object as params value.

Note that here we're talking about params appended to URL (query params), which is explicitly mentioned in the documentation.

If you want to send something within request body with GET requests, params won't work - and neither will data, as it's only taken into account for PUT, POST, DELETE, and PATCH requests. There're several lengthy discussions about this feature, and here's the telling quote:

Unfortunately, this doesn't seem to be an axios problem. The problem seems to lie on the http client implementation in the browser javascript engine.

According to the documentation and the spec XMLHttpRequest ignores the body of the request in case the method is GET. If you perform a request in Chrome/Electron with XMLHttpRequest and you try to put a json body in the send method this just gets ignored.

Using fetch which is the modern replacement for XMLHtppRequest also seems to fail in Chrome/Electron.

Until it's fixed, the only option one has within a browser is to use POST/PUT requests when data just doesn't fit into that query string. Apparently, that option is only available if corresponding API can be modified.

However, the most prominent case of GET-with-body - ElasticSearch _search API - actually does support both GET and POST; the latter seems to be far less known fact than it should be. Here's the related SO discussion.

How about using direct axios API?

axios({
  method: 'post',
  url: baseUrl + 'applications/' + appName + '/dataexport/plantypes' + plan,
  headers: {}, 
  data: {
    foo: 'bar', // This is the body part
  }
});

Source: axios api

It is NOT possible to pass data inside a body on a GET request.

GET request only allow you to pass values via the Params or Headers.

Backend E. g.:

const data = req.query.data;

Frontend E. g.:

const headers = {
    'Authorization': `Bearer ${token}`
};

const params = {
    data: 'Some Text'
};
            
const data = await axios.get(
    "http://localhost:5000/api/data",
    { headers, params }
);

If you want to pass data in the body, you could also change the method to POST -- if there is no other way around.

In general there is no point in a body for GET requests, so axios does not support it.

If you read the axios config documentation, you will find

// data is the data to be sent as the request body
// Only applicable for request methods 'PUT', 'POST', 'DELETE , and 'PATCH'

You can read more at HTTP GET with request body for the reasons.

If you want to send data in a GET request use the params property

// params are the URL parameters to be sent with the request
// Must be a plain object or a URLSearchParams object

Not all clients and servers support body in GET request. In this case, the browser can't send body in GET request (axios supports sending body in GET request).

As a workaround, you can change the method from 'GET' to 'POST'

Like so:

axios.request({
  method: 'POST',
  url: `http://localhost:4444/next/api`,
  headers: {
    'Authorization': token
  },
  data: {
    next_swastik: 'lets add something here'
  },

})

and change your api to expect a post

app.post('/next/api', verifyToken, function(req, res) {
console.log(req.body);
});

or

Change the data property to params

axios.request({
  method: 'GET',
  url: `http://localhost:4444/next/api`,
  headers: {
    'Authorization': token
  },
  params: {
    next_swastik: 'lets add something here'
  },

})

and change the api to log out the params

app.get('/next/api', verifyToken, function(req, res) {
console.log(req.params);
});

and like @MaieonBrix said, make sure that your headers contain the content type that you are sending.