Skip to main content

Dart 1.23: Better strong mode support

Dart 1.23 is now available. It introduces support for overriding fields in strong mode and a lot of other improvements. Get it now!

Screen Shot 2017-04-21 at 16.15.20.png
Figure 1: Overriding fields in strong mode

We have been spending a lot of our time on our unified front-end (explained by Vyacheslav Egorov in this short talk from the Dart Developer Summit). We're also doing a lot of work to support our critical customers (for example, Flutter gets better Windows support with this release) and solidifying strong mode.

Some notable changes in this release:
  • Overriding fields is now supported in strong mode. You don’t need to tag them with @virtual anymore.
  • Strong mode inference error messages are more helpful.
  • Strong mode now prefers the expected type to infer generic types, functions, and methods.
  • The UriData.parse method now normalizes and validates its input better.
  • Importing dart:io is now allowed in the browser, as a stopgap measure to make it easier to write libraries that share code between platforms (like package http that needs to run in the browser, on mobile, and on the command line).
  • pub publish now warns you when you’re importing a package that is not a direct dependency in pubspec.yaml.
  • pub get/upgrade now produces a more informative error message for Flutter.
  • dartfmt now makes precedence of cascades more visible, and adds other small formatting tweaks.
  • Fixes for Unicode character printing in the Windows console, inconsistencies between dartanalyzer and the analysis server in finding the options file, pub “UID too large” errors on OS X, and more.
For more information, see the changelog.

Please download the latest release and let us know what you think!

Comments

Popular posts from this blog

Const, Static, Final, Oh my!

Posted by Seth Ladd

(This is an "oldie but a goodie" misc@dartlang.org post originally written by Bob Nystrom. It is being posted here as the explanations still ring true.)

Bob writes:


"static", "final", and "const" mean entirely distinct things in Dart:

"static" means a member is available on the class itself instead of on instances of the class. That's all it means, and it isn't used for anything else. static modifies *members*.

"final" means single-assignment: a final variable or field *must* have an initializer. Once assigned a value, a final variable's value cannot be changed. final modifies *variables*.

"const" has a meaning that's a bit more complex and subtle in Dart. const modifies *values*. You can use it when creating collections, like const [1, 2, 3], and when constructing objects (instead of new) like const Point(2, 3). Here, const means that the object's entire deep state can be determ…

Dart 1.12 Released, with Null-Aware Operators and more

Dart 1.12.0 is now released! It contains the new null-aware operators language feature, and enhancements to pub, Observatory, dartdoc, and much more.

Null-aware operators

The new null-aware operators help you reduce the amount of code required to work with references that are potentially null. This feature is a collection of syntactic sugar for traversing (potentially null) object calls, conditionally setting a variable, and evaluating two (potentially null) expressions.

Click or tap the red Run button below to see them in action.

??

  if null operator. `expr1 ?? expr2` evaluates to `expr1` if not `null`, otherwise `expr2`.


??=

  null-aware assignment. `v ??= expr` causes `v` to be assigned `expr` only if `v` is `null`.

x?.p

  null-aware access. `x?.p` evaluates to `x.p` if `x` is not `null`, otherwise evaluates to `null`.

x?.m()

  null-aware method invocation. `x?.m()` invokes `m` only if `x` is not `null`.

Learn more about Dart's null-aware operators in our Language Tour.

.packages fi…

The new AdWords UI uses Dart — we asked why

Google just announced a re-designed AdWords experience. In case you’re not familiar with AdWords: businesses use it to advertise on google.com and partner websites. Advertising makes up majority of Google’s revenue, so when Google decides to completely redo the customer-facing front end to it, it’s a big deal. The Dart team is proud to say that this new front end is built with Dart and Angular 2. Whenever you asked us whether Google is ‘even using Dart for anything,’ this is what we had in mind but couldn’t say aloud. Until now. We asked Joshy Joseph, the primary technical lead on the project, some questions. Joshy is focusing on things like infrastructure, application latency and development velocity, so he’s the right person to ask about Dart.Q: What exactly did we launch on Monday?It’s a complete redesign of the AdWords customer experience that is rolling out slowly as a test to a small initial set of advertisers. The most noticeable thing is probably the Material Design look and f…