React form submit is creating phantom parameters - ruby-on-rails

Question

I have a basic registration form in a React front end app, that sends the input parameters to a rails-api backend.
The function to do so looks like this:
handleSubmit(event) {
event.preventDefault();
Axios.post('http://localhost:3001/auth/', {
'password': 'password',
'password_confirmation': 'password',
'email': 'asdf#asdf',
'first_name': 'asdfasdf',
'last_name': 'wefawa',
'handle': 'awfewwe'
})
.then(function (response) {
alert(response);
console.log(response);
})
.catch(function (error) {
console.log(error);
});
}
When I send this though, the params on the rails-api backend somehow include a second copy of each parameter, nested under the key "registrations" The full text, copied from console logs:
"Started POST "/auth/" for ::1 at 2018-01-12 00:36:07 -0500
Processing by Overrides::RegistrationsController#create as HTML
Parameters: {"password"=>"[FILTERED]", "password_confirmation"=>"[FILTERED]", "email"=>"asdf#asdf", "first_name"=>"asdfasdf", "last_name"=>"wefawa", "handle"=>"awfewwe", "registration"=>{"password"=>"[FILTERED]", "password_confirmation"=>"[FILTERED]", "email"=>"asdf#asdf", "first_name"=>"asdfasdf", "last_name"=>"wefawa", "handle"=>"awfewwe"}}"
Any idea where that registration tag is coming from?
I realize this is a rather specific question, but any help is much appreciated.
Thanks!

Answer 1

My Own Answer
I had to rearrange the syntax somewhat, but the following worked:
handleSubmit(event) {
event.preventDefault();
Axios.request({
url: 'http://localhost:3001/auth/',
method: 'post',
params: {
'password': 'password',
'password_confirmation': 'password',
'email': 'possible2#example.com',
'first_name': 'asdfasdf',
'last_name': 'wefawa',
'handle': '#notusedyet2'
},
headers: {
'Content-Type': 'multipart/form-data'
}
})
.then(function (response) {
console.log(response);
})
.catch(function (error) {
console.log(error);
});
}