實驗性的引數標記
The Dart SDK often contains experimental features, which you can try by passing flags to Dart tools.
Using experiment flags with command-line tools
To use an experiment with Dart SDK command line tools,
pass the corresponding flag to the tool.
For example, to enable the experiments
super-mixins and no-slow-checks,
add those flags to the dart command:
$ dart run --enable-experiment=super-mixins,no-slow-checks bin/main.dart
Using experiment flags with the Dart analyzer (command-line and IDE)
To enable experiments affecting analysis,
use the enable-experiment key in the analysis options file.
Here’s an example of enabling the experiments
super-mixins and no-slow-checks in analysis_options.yaml:
analyzer:
  enable-experiment:
    - super-mixins
    - no-slow-checks
Using experiment flags with IDEs
To enable experiments related to running or debugging apps in IDEs, edit the launch configuration.
Visual Studio Code
In launch.json under configurations,
add a new toolArgs key containing the desired flags.
Example:
 "configurations": [
        {
            "name": "Dart",
            "program": "bin/main.dart",
            "request": "launch",
            "type": "dart",
            "toolArgs": [
                "--enable-experiment=super-mixins,no-slow-checks",
            ],
        }
    ]
For more information, consult the documentation for VS Code launch configurations.
Android Studio
Under VMOptions add the desired flags.
Example:
<component name="ProjectRunConfigurationManager">
  <configuration default="false" name="Run main" type="DartCommandLineRunConfigurationType" factoryName="Dart Command Line Application">
    <option name="VMOptions" value="--enable-experiment=non-nullable" />
    <option name="filePath" value="$PROJECT_DIR$/bin/main.dart" />
    <method v="2" />
  </configuration>
</component>
For more information, consult the instructions for Android Studio run/debug configurations.
More information
- For a complete list of experiments,
see the Dart SDK file experimental_features.yaml.
- For information on procedures and expectations for experiment flags, see the documentation of the process for changes that are behind experimental flags.