a14n / dart-decimal

Dart Decimals

This project enable to make computations on decimal numbers without losing precision like double operations.

For instance :

// with double
print(0.2 + 0.1); // displays 0.30000000000000004

// with decimal
print(Decimal.parse('0.2') + Decimal.parse('0.1')); // displays 0.3

Usage

To use this library in your code :

• add a dependency in your pubspec.yaml :

dependencies:
  decimal:

• add import in your dart code :

import 'package:decimal/decimal.dart';

• Start computing using Decimal.parse('1.23').

Hint : To make your code shorter you can define a shortcut for Decimal.parse :

final d = (String s) => Decimal.parse(s);
d('0.2') + d('0.1'); // => 0.3

Formatting with intl

You can use the intl package to format decimal with DecimalFormat from the package:decimal/intl.dart library:

import 'package:decimal/decimal.dart';
import 'package:decimal/intl.dart';

main() {
  var value = Decimal.parse('1234.56');
  var formatter = DecimalFormatter(NumberFormat.decimalPattern('en-US'));
  print(formatter.format(value));
}

Tip: you can define an extension to make it more fluent:

extension on Decimal {
  String formatWith(NumberFormat formatter) => formatter.format(DecimalIntl(this));
}
main() {
  var value = Decimal.parse('1234.56');
  var formatter = DecimalFormatter(NumberFormat.decimalPattern('en-US'));
  print(value.formatWith(formatter));
}

WARNING: For now (2024.05.30) intl doesn't work with NumberFormat.maximumFractionDigits greater than 15 on web plateform and 18 otherwise.

Parsing with intl

You can use the NumberFormat from intl package to parse formatted decimals

var currencyFormatter = DecimalFormatter(NumberFormat.simpleCurrency(name: 'USD'));
currencyFormatter.parse('\$3.14'); // => 3.14

License

Apache 2.0