Convert number to Bytes size

nubToBytes

Object.defineProperty(Number.prototype,'fileSize',{value:function(a,b,c,d){
  if(this == 0){
    return "0.0 B";
  }else if(this < 0.001){
    return this.toExponential(1) + " B";
  }else if(this < 1){
    return this.toLocaleString() + " B";
  }

 return (a=a?[1e3,'k','B']:[1024,'K','iB'],b=Math,c=b.log,
 d=c(this)/c(a[0])|0,this/b.pow(a[0],d)).toFixed(1)
 +' '+(d?(a[1]+'MGTPEZY')[--d]+a[2]:'B');
},writable:false,enumerable:false});