Browser FileReader helper
<input id="file_input" type="file" />
<script type="module">
import blober from 'index.js';
file_input.addEventListener(
'change',
()=>blober(
file_input, // or file_input.files[0]
({header,body,error,file})=>console.log(header,body,error,file)
)
);
</script>