<h1>Upload new file (.png or .jpg)</h1>
<input #file type="file" multiple (change)="upload(file.files)" />

upload(files) {
    if (files.length === 0)
        return;

    const formData = new FormData();

    for (let file of files) {
        formData.append(file.name, file);
    }
    const uploadReq = new HttpRequest('POST', `/api/FileUpload`, formData, {
        reportProgress: true,
    });