Form Submit with Multiple Images in Vue JS2

I am Continuing My Form Upload with Multiple Images in Extension to the Object oriented Forms

Tutotrial Of Vue JS 2 but found so many problems but finally i am struck at a point my code is

//Form.js

import Errors from './Errors';
class Form {
    /**
     * Create a new Form instance.
     *
     * @param {object} data
     */
    constructor(data) {
        this.originalData = data;
        for (let field in data) {
            this[field] = data[field];
        }
        this.errors = new Errors();
    }

    /**
     * Fetch all relevant data for the form.
     */
    data() {
        let data = new FormData();
        for (let property in this.originalData) {
            data.append(property,this[property]);
        }
        return data;
    }

    /**
     * Reset the form fields.
     */
    reset() {
        for (let field in this.originalData) {
            this[field] = '';
        }
        this.errors.clear();
    }

    /**
     * Send a POST request to the given URL.
     * .
     * @param {string} url
     */
    post(url) {
        return this.submit('post', url);
    }

    /**
     * Send a PUT request to the given URL.
     * .
     * @param {string} url
     */
    put(url) {
        return this.submit('put', url);
    }

    /**
     * Send a PATCH request to the given URL.
     * .
     * @param {string} url
     */
    patch(url) {
        return this.submit('patch', url);
    }

    /**
     * Send a DELETE request to the given URL.
     * .
     * @param {string} url
     */
    delete(url) {
        return this.submit('delete', url);
    }

    /**
     * Submit the form.
     *
     * @param {string} requestType
     * @param {string} url
     */
    submit(requestType, url) {
        return new Promise((resolve, reject) => {
            axios[requestType](url, this.data(),{headers:{'Content-Type':'multipart/form-data'}})
                .then(response => {
                    this.onSuccess(response.data);
                    resolve(response.data);
                })
                .catch(error => {
                    this.onFail(error.response.data);
                    reject(error.response.data);
                });
        });
    }

    /**
     * Handle a successful form submission.
     *
     * @param {object} data
     */
    onSuccess(data) {
        alert(data.message); // temporary
        this.reset();
    }

    /**
     * Handle a failed form submission.
     *
     * @param {object} errors
     */
    onFail(errors) {
        this.errors.record(errors);
    }
}
export default Form;


// App.js

import Form from "./Form";
var app = new Vue({
    el: '#app',
    data: {
        form: new Form({
            name: '',
            description: '',
            image:[]
        })
    },
    methods: {
        onFileChange(e){
            let selDiv = document.querySelector('#preview');
            if (!e.target.files || !window.FileReader) return;
            selDiv.innerHTML = "";
            let files = e.target.files, filesArr = Array.prototype.slice.call(files);
            filesArr.forEach(f => {
                if (!f.type.match('image.*')) {
                    e.target.value = e.target.type = '';
                    e.target.type = 'file';
                    alert('We accept only images');
                }
                app.$data.form.image.push(f);
                var reader = new FileReader();
                reader.onload = function (c) {
                    var html = "<img src='" + c.target.result + "' class='preview-img' height='80'>";
                    selDiv.innerHTML += html;
                }
                reader.readAsDataURL(f);
            });
        },
        onSubmit() {
            this.form.post('/projects')
        }
    }
});

here I want to know how to add file object to the FormData() and send it to the server