How do I send a post request with axios? (CountriesNow API)

I’m trying to get the cities from Romania using the countriesnow api, however, I am always receiving the following message:
{"error":true,"msg":"missing param (country)"}
I’ve followed the documentation for axios, but it doesn’t seem to work.

This is my code:

var data = '{\n    "country": "romania"\n}';

    axios({
        method: 'post',
        headers: {},
        url: 'https://countriesnow.space/api/v0.1/countries/cities',
        data: data
    })
        .then((response) => {
            console.log(response.data);
        })
        .catch((error) => {
            console.log(error);
        });

It however works with postman:

>Solution :

var data = {
  country: "romania"
};

And the same to all.

If it doesn’t work for you, I suggest to append the data to form data like the following.

const data = new FormData();
data.append('country','romania');

// same

Please refer to this.
https://masteringjs.io/tutorials/axios/axios-multi-form-data#:~:text=To%20send%20multipart%20form%20data,using%20the%20append()%20method.