Function retainDecimalsByDigit

Remarks

保留小数，不存在精度丢失问题,解决使用toFixed精度丢失或者大数等问题

Returns

返回数据结果 使用demo如下：

console.log(retainDecimalsByDigit(-12334577));
console.log(5.215.toFixed(2),1.125.toFixed(2) )// 结果分别为 5.21 1.13  5.215 存在精度丢失
console.log(retainDecimalsByDigit(5.215,2),retainDecimalsByDigit(1.125,2)); // 结果分别为 5.22 1.13 不存在精度丢失
console.log(retainDecimalsByDigit(12334577));//12334577.00
console.log(retainDecimalsByDigit(-12334577.12,5));//-12334577.12000
console.log(retainDecimalsByDigit(-12334577.12,5,false,false));//-12334577.12
console.log(retainDecimalsByDigit(-12334577.125,2));//-12334577.13
console.log(retainDecimalsByDigit(-12334577.124,2,false,false));//-12334577.12
console.log(retainDecimalsByDigit(-12334577.9999,2));//-12334578.00
console.log(retainDecimalsByDigit(-12334577.9999,2,false,false));//-12334577.99
console.log(retainDecimalsByDigit('199.99999999999999999999999999',2));//200.00
console.log(retainDecimalsByDigit('198.19999999999999999999999999',2));// 198.20
console.log(411522199010154219.99999999999999999999999999.toFixed(2))//结果 411522199010154240.00 
console.log(retainDecimalsByDigit('411522199010154219.99999999999999999999999999'))//结果 411522199010154220.00
console.log(retainDecimalsByDigit('9999999999999999.99999999999999999999999999',4));// 10000000000000000.0000