CODE EXAMPLE FOR JAVASCRIPT

axios post form data and json

doAjaxPost() {
    var formData = new FormData();
    var file = document.querySelector('#file');

    formData.append("file", file.files[0]);
    // formData.append("document", documentJson); instead of this, use the line below.
    formData.append("document", JSON.stringify(documentJson));

    axios({
        method: 'post',
        url: 'http://192.168.1.69:8080/api/files',
        data: formData,
    })
    .then(function (response) {
        console.log(response);
    })
    .catch(function (response) {
        console.log(response);
    });
}