digitafterdecimal.dart

void main() {
  print(30.88922.withDecimalPoints(3)); //30.889
  print(30.88922.withDecimalPointsFormatted(1)); //30.9
  print(30.withDecimalPoints(3)); //30.0
  print(30.withDecimalPointsFormatted(3)); //30.000
}

extension DecimalPoints on num {
  double withDecimalPoints(int n) {
    return num.parse(this.toStringAsFixed(n));
  }

  // Adds necessary non significant 0s at end for formatting
  String withDecimalPointsFormatted(int n) {
    var numString = this.withDecimalPoints(n).toString();
    var missingZeros = n - numString.split(".")[1].length;
    return numString + "0" * missingZeros;
  }
}