To post request with JSON data with Axios, we call axios.post with the JSON payload as the 2nd argument.

For instance, we write

const dt = { data: { value: "abc" } };
const request = axios.post(url, dt);

to call axios.post with the request url and dt JSON request payload data.

Therefore, { data: { value: "abc" } } is the JSON request data for this POST request.