crc32 unsigned

-demo https://codepen.io/gnjo/pen/NVWdLd?editors=1010
-zeropadding tohex unsigned

let fn={}
fn.crcTable=(function(){
  var c,crcTable = [];
  for(var n =0; n < 256; n++){
    c = n;
    for(var k =0; k < 8; k++){
      c = ((c&1) ? (0xEDB88320 ^ (c >>> 1)) : (c >>> 1));
    }
    crcTable[n] = c;
  }
  return crcTable;
})();//early gen
fn.crc32 = function(str,hex=true) {
  var crcTable = fn.crcTable,pad=( (d,l)=>('000000000000000000'+d).slice(-1*l))
  ,crc = 0 ^ (-1)
  ;
  for (var i = 0; i < str.length; i++ ) crc = (crc >>> 8) ^ crcTable[(crc ^ str.charCodeAt(i)) & 0xFF]
  ;
  crc = (crc ^ (-1)) >>> 0
  ;
  return (hex)?pad(crc.toString(16),8):crc
}

/*
fn.crc32('xyz')
*/