Run results for: ByteByte

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:90.0) Gecko/20100101 Firefox/90.0

Browser: Firefox 90

Operating system: Mac OS X 10.15

Device Platform: Desktop

Date tested: 3 years ago

Test name	Executions per second
f1	74983.9 Ops/sec
f2	55410.0 Ops/sec
f3	124621.2 Ops/sec
f4	83763.1 Ops/sec
f5	53666.4 Ops/sec

Script Preparation code:

function format1(bytes) {
   var sizes = ['Bytes', 'KB', 'MB', 'GB', 'TB'];
   if (bytes == 0) return '0 Byte';
   var i = parseInt(Math.floor(Math.log(bytes) / Math.log(1024)));
   return Math.round(bytes / Math.pow(1024, i), 2) + ' ' + sizes[i];
}


function format2(bytes, decimals = 2) {
    if (bytes === 0) return '0 Bytes';

    const k = 1024;
    const dm = decimals < 0 ? 0 : decimals;
    const sizes = ['Bytes', 'KB', 'MB', 'GB', 'TB', 'PB', 'EB', 'ZB', 'YB'];

    const i = Math.floor(Math.log(bytes) / Math.log(k));

    return parseFloat((bytes / Math.pow(k, i)).toFixed(dm)) + ' ' + sizes[i];
}

function format3(bytes) {
    var marker = 1024; // Change to 1000 if required
    var decimal = 3; // Change as required
    var kiloBytes = marker; // One Kilobyte is 1024 bytes
    var megaBytes = marker * marker; // One MB is 1024 KB
    var gigaBytes = marker * marker * marker; // One GB is 1024 MB
    var teraBytes = marker * marker * marker * marker; // One TB is 1024 GB

    // return bytes if less than a KB
    if(bytes < kiloBytes) return bytes + " Bytes";
    // return KB if less than a MB
    else if(bytes < megaBytes) return(bytes / kiloBytes).toFixed(decimal) + " KB";
    // return MB if less than a GB
    else if(bytes < gigaBytes) return(bytes / megaBytes).toFixed(decimal) + " MB";
    // return GB if less than a TB
    else return(bytes / gigaBytes).toFixed(decimal) + " GB";
}


const units = ['bytes', 'KB', 'MB', 'GB', 'TB', 'PB', 'EB', 'ZB', 'YB'];
   
function format4(x){

  let l = 0, n = parseInt(x, 10) || 0;

  while(n >= 1024 && ++l){
      n = n/1024;
  }
  
  return(n.toFixed(n < 10 && l > 0 ? 1 : 0) + ' ' + units[l]);
}

function format5(bytes){
  var kb = 1024;
  var ndx = Math.floor( Math.log(bytes) / Math.log(kb) );
  var fileSizeTypes = ["bytes", "kb", "mb", "gb", "tb", "pb", "eb", "zb", "yb"];

  return {
    size: +(bytes / kb / kb).toFixed(2),
    type: fileSizeTypes[ndx]
  };
}

Tests:

f1
for(var i =0; i<100; i++){ var a = format1(i*1024); }
f2
for(var i =0; i<100; i++){ var a = format2(i*1024); }
f3
for(var i =0; i<100; i++){ var a = format3(i*1024); }
f4
for(var i =0; i<100; i++){ var a = format4(i*1024); }
f5
for(var i =0; i<100; i++){ var a = format5(i*1024); }

bytymighty

f1

f2

f3

f4

f5