This package is a polyfill for the core library constant names that are changing from Dart 1 to Dart 2.
In Dart 1, all core library constants were in SCREAMING_CAPS. In Dart 2, they're being changed to camelCase. This package makes it possible for packages to support both Dart 1 and Dart 2 by providing camelCase constants that work on all versions of Dart.
This package has a library for each library dart: library that contained constants in Dart 1. These libraries contain only constants, using the Dart 2 names. They should be imported using a prefix so as to avoid colliding with core library names:
import 'package:dart2_constant/convert.dart' as convert; String decodeUtf8(List<int> bytes) => convert.utf8.decode(bytes);
Note that this even supports constants that haven't yet migrated in the core libraries, such as those in dart:io and dart:html. These are provided for compatibility with future SDK changes.
Each version of dart2_constant has two releases, one tagged +dart1 that‘s only compatible SDKs that have old-style constants and one tagged +dart2 that’s only compatible with SDKs that have new-style constants. As long as you depend on dart2_constant, pub's version solver will make sure your users get a version of it that works for them.
The dart2_fix package can be used to automatically migrate constant references from Dart 1 style to Dart 2 style. It doesn't currently support migrating to dart2_constant references, though.