回应没有用axios带回数据

Question

I have a function in php, that returns the json_encoded version of a string, but when I console.log the response gotten from the json_encoded data in my react app, through axios, the data is usually empty,usually like this,Object {data: "", status: 200, statusText: "OK", headers: Object, config: Object…} ,Please what may be the issue

PHP FILE

header("Access-Control-Allow-Origin: *");
return json_encode("works");

React file

import axios from 'axios';
class LoginComponent extends Component {
componentDidMount() {
    axios.get('http://localhost/login.php')
        .then(response => {
            console.log(response);
        })
        .catch(function (error) {
            console.log(error);
        })
    }