thanOrEqualDecString method
Relational less than or equal operator. 判断a是否小于或者等于b
Implementation
bool thanOrEqualDecString(String a, String b) {
final aDecimal = _safeParseDecimal(a);
final bDecimal = _safeParseDecimal(b);
if (aDecimal == null || bDecimal == null) return false;
return aDecimal <= bDecimal;
}