Making possibility to upload files to the site but in such a way that folders cannot be uploaded. Wrote a function that checks it.
function notADirectory(maybeFile) {    // maybeFile ~ new File()
    if (maybeFile.type !== '') return true;
    const reader = new FileReader()
    reader.onloadend = () => !(reader.error && 
        (reader.error.name === 'NotFoundError' || reader.error.name === 'NotReadableError'))
    reader.readAsBinaryString(maybeFile)
}
But there is a text.psd photoshop file and for some reason js does not see the type in it - it is empty. Because of this, the function does not work properly.
Is there any other proper way to check file on directory?
Adding directory="" webkitdirectory="" into html input is not suitable because there is also possibility to add files on site with Ctrl + V and dragging it on page