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Release Notes for Dart's Beta Release

Today's release of the Dart SDK and Editor is the first beta release, and contains performance and productivity improvements across the platform. This latest release helps Dart developers automate code evolution, produce smaller JavaScript code and deploy Dart web apps.

The major additions and changes to the platform include:



  • dart2js
    • Added support for dart:typed_data
    • Improved type inferrer by using union types and keeping track of side effects
    • Implemented sharing of code mixed into multiple classes
    • More coverage for handling of generic type
    • Performance improvements
      • 20% faster on Richards, 10% faster on DeltaBlue, 8% faster on Tracer
    • Significant progress on mirrors support (work in progress)
  • Dart VM
    • DeltaBlue: 40% faster than M4
    • Tracer: 33% faster than M4
    • Full SIMD acceleration
    • Reduced initial snapshot size
      • improves startup time for new isolates
    • Improved stability of debugging experience
  • Editor
    • A new 20% faster Analyzer in Editor and SDK.
      • Remove old analyzer.
    • More quick fixes and refactorings in Editor.
    • Code Folding has returned with the new ability to collapse classes and local functions.
    • Mark Occurrences is back.
    • New Pub Deploy command.
    • Many Code Completion enhancements
      • Proposal filtering now accepts camelCase input (e.g., type 'i' then 'E' to filter out everything except isEmpty).
      • Unused optional parameters are deleted automatically after template editing is done.
      • Requesting completion in an empty argument list will include an option to insert the argument template.
      • The seed is now case-insensitive (e.g., map.isemp+Ctrl-Space -> map.isEmpty).
  • Greatly improved WebGL performance in Dartium because of move to dart:typed_data library for typed arrays.
  • Libraries
    • dart:async
      • Stream bugfixing (one breaking change: disallow re-subscribing to cancelled stream)
    • dart:core
      • Allow Pattern (like String and RegExp) in more places.
    • dart:uri
      • Functionality moved to dart:core, API improved, stable.
  • dart:crypto
    • Not essential to have as a dart: library at this point. Moved to a pub package.
  • dart:io
    • Added IPv6 support
    • Improved speed and stability of HTTP and Web Sockets. HTTP handing is now more than 50% faster
    • Better support for processing HTTP bodies
    • Improved HTTP authentication and proxy support
  • pub:
    • New backtracking version solver, SDK version constraints
    • Add offline mode
    • Initial version of pub deploy
  • html:
    • New dart:mdv_observe library
    • Typed_data
  • dartium: devtools improvements
    • Repl-style behavior including creating new Dart objects from the console
    • Mouse over of Dart fields and getters now displays their values
    • Fewer crashes
  • Web UI
    • New polymer branch, implementing Web UI with Polymer polyfills (work in progress)

    You can download the latest version of Dart Editor, including everything you need for Dart development, from dartlang.org. We look forward to your feedback!

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