make_file_reader = default_text => {
var dom = html`<div><input type='file' accept='*'>`;
var inp = dom.getElementsByTagName('input')[0];
var r = new FileReader();
dom.value = default_text;
r.onload = () => {
dom.value = r.result;
dom.dispatchEvent(new CustomEvent("input"));
};
inp.addEventListener('change', () => {
r.readAsText(inp.files[0]);
});
return dom;
}