var dataObj = {username:"username",password:"password",data1:"data1"};

{dataObj:{username:"username",password:"password",data1:"data1"}};

{username:"username",password:"password",data1:"data1"}

axios.post('http://192.168.1.1xx:3000/data', {
    dataObj
})
.then(function (response) {
    console.log(response);
})
.catch(function (error) {
    console.log(error);
});