ethers 处理余额显示

let b = utils.formatUnits('bignumber'.toString(), 9); let str1 = b.toString().replace(/\d+\.(\d*)/, "$1"); let str2 = b.substring(0, b.indexOf(".")); let str3 = toThousands(str2); b = str3 + "." + str1;       const toThousands = (num) => {   let result = "",     counter = 0;   num = (num || 0).toString();   for (let i = num.length - 1; i >= 0; i--) {     counter++;     result = num.charAt(i) + result;     if (!(counter % 3) && i != 0) {       result = "," + result;     }   }   return result; };