adaptive_number_dart

adaptive_number

A library providing a Number implementation that is dependent on the platform it is compiled for. For JS runtimes, the implementation uses a 64-bit signed fixed-width integer, for all other platforms the default Dart int data type.

Use cases of this library

The Number substitute is useful in situations where a value may overflow on JS runtimes since the available value range is not the same compared to mobile or desktop platforms:

https://api.dart.dev/stable/2.8.4/dart-core/int-class.html

The overflow on JS environments can be circumvented by using a BigInt or the fixed-with implementation of this library: https://pub.dev/packages/fixnum

The disadvantage of just replacing all usages of int with BigInt or fixnum/Int64 is that the performance on mobile platforms may suffer significantly.

The adpative_number library takes a conditional import approach to ease this problem:

• If it runs on a JS runtime, Number wraps a fixnum/Int64
• For all other platforms Number wraps a default Dart int type.

Some historical background of this library can also be seen in: https://github.com/MixinNetwork/libsignal_protocol_dart/pull/43

Usage

A Number instance is created by wrapping it around a default int value:

import 'package:adaptive_number/adaptive_number.dart';

void main() {
  final number1 = Number(93432);
  final number2 = Number(42435);
  assert((number1 + number2) == Number(51777));
}

All other operations on Number behave the same way as with int.

Features and bugs

Please file feature requests and bugs at the issue tracker.