bytes to filesize javascript

humanfilesize

function humanFileSize(bytes, pre, si) {
  // Set default args
    si = typeof si ===  'undefined' ? true:false;
    pre = typeof pre ===  'undefined' ? 0:pre;

    var thresh = si ? 1000 : 1024;
    if(Math.abs(bytes) < thresh) {
        return bytes.toFixed(pre) + ' B';
    }
    var units = si
        ? ['kB','MB','GB','TB','PB','EB','ZB','YB']
        : ['KiB','MiB','GiB','TiB','PiB','EiB','ZiB','YiB'];
    var u = -1;
    do {
        bytes /= thresh;
        ++u;
    } while(Math.abs(bytes) >= thresh && u < units.length - 1);
    return bytes.toFixed(pre)+ ' ' +units[u];
}

console.log(humanFileSize(1, 2))