function a(b){
console.log(b);
}
// fundation
function c(str){
let split = str.split(".");
let int = split[0],
len = int.length,
ret = "";
//core code
while((len -= 3) > 0){
ret = ","+int.substring(len,len+3)+ret;
}
ret = int.substring(0,len+3)+ret;
if(split.length>1){
ret += "."+split[1];
}
return ret;
}
function d(str){
let start = new Date().getTime();
let ret = c(str);
a("ET: "+ (new Date().getTime()-start)+" ms");
return ret;
}
//for test
a(d(""));
a(d("1234"));
a(d("1234567890.123456"));
let startt = new Date().getTime();
let str = "1234567890.123456";
let k = 0;
while(k++<2000000){
c(str)
}
a("ET: "+ (new Date().getTime()-startt)+" ms/2000000");
