Dart

With IntelliJ IDEA, you can develop, run, and debug Dart web and command-line applications. IntelliJ IDEA helps you providing code completion, error and syntax highlighting, code inspections and quick-fixes, search and navigation, refactoring, and much more. IntelliJ IDEA also integrates with the pub tool and the Dart Analysis Server.

Before you start

Install and enable the Dart plugin on the Settings/Preferences | Plugins page, tab Marketplace, as described in Installing plugins from JetBrains repository.

Downloading the Dart tools

Download and install the Dart SDK.

The Dart SDK contains all the tools for developing both command-line and web Dart applications. It incorporates the Dart Virtual Machine, the Dart core Libraries, as well as all the command-line tools, including compilers (dart2js and dartdevc ), the dartfmt code formatter, and the pub tool.

Learn more about the Dart development tools from the Dart official website.

Creating a new Dart application

If you have no application yet, you can generate a IntelliJ IDEA project with Dart-specific structure from a Stagehand template. Alternatively, create an empty IntelliJ IDEA project and configure Dart support in it as described in Starting with an existing Dart application below.

Create a Dart project from a Stagehand template

Select File | New | Project from the main menu or click the New Project button on the Welcome screen.
In the New Project dialog, select Dart in the left-hand pane.
In the right-hand pane, specify the path to the Dart SDK. IntelliJ IDEA detects and displays the Dart version.
To have a sample application created in the project, select the Generate sample content checkbox and choose the relevant Stagehand template from the list below. If you clear the checkbox, IntelliJ IDEA creates an empty project.
Click Next.
On the second page of the wizard, specify the project name and the path to the folder where the project-related files will be stored. When you click Finish, IntelliJ IDEA sets up the project structure and generates some sources based on the selected Stagehand template.

Create an empty IntelliJ IDEA project

Select File | New | Project from the main menu or click the New Project button on the Welcome screen.
In the New Project dialog, select JavaScript in the left-hand pane.
In the right-hand pane, again choose JavaScript and click Next.
On the second page of the wizard, specify the project folder and name and click Finish.

Starting with an existing Dart application

If you are going to continue developing an existing Dart application, open it in IntelliJ IDEA, configure Dart in it, and download the required dependencies as described in Managing Dart dependencies below.

Open the application sources that are already on your machine

Click Open or Import on the Welcome screen or select File | Open from the main menu. In the dialog that opens, select the folder where your sources are stored.

Check out the application sources from your version control

Click Get from VCS on the Welcome screen or select VCS | Get from Version Control from the main menu.
In the invoked dialog, select your version control system from the list and specify the repository to check out the application sources from.

Configure Dart support in an existing project

In Settings/Preferences dialog Ctrl+Alt+S, choose Dart under Languages and Frameworks. The Dart page opens.
Select the Enable Dart support for the project <project name> checkbox.
In the Dart SDK Path field, specify the location of the downloaded Dart SDK. Type the path manually or click and choose the path in the dialog box that opens. If IntelliJ IDEA recognizes the Dart SDK correctly, its revision number is displayed in the Version read-only field.
In the Enable Dart support for the following modules area, select the checkboxes next to the names of the modules where you need Dart support.

Working with several Dart projects (packages) in one IntelliJ IDEA project

To attach a Dart project (package) to an existing IntelliJ IDEA project you need to add its root folder as a content root or as a new module.

Add a Dart project (package) to an existing IntelliJ IDEA project

Add a content root on the Modules page (File | Project Structure | Modules) as described in Adding a content root.
Add a module to your project: choose File | New | Module from Existing Sources and select the relevant module in the dialog that opens.

Managing Dart dependencies

IntelliJ IDEA integrates with the pub tool and lets you run its actions right from the editor. As soon as you open a pubspec.yaml file, IntelliJ IDEA displays a pane at the top of its editor tab. Use the links on this pane to invoke pub get, pub upgrade, and pub outdated actions.

Alternatively open pubspec.yaml in the editor or select it in the Project tool window and invoke pub actions from the context menu of the selection.

You can also use the tool in the command-line mode from the Terminal.

The pub tool saves the downloaded packages in the cache and creates a .packages file and a pubspec.lock file next to the pubspec.yaml file.

IntelliJ IDEA logs execution of pub commands in the Messages tool window where you can also re-run the last executed command by clicking on the toolbar.

Building a Dart application

Open the pubspec.yaml file in the editor or switch to the tab where it is opened.
On the pane at the top of the tab, click Webdev build.... This invokes the webdev build action.
In the dialog that opens, specify the input folder to take the sources from and the output folder where you want the compiled application stored.

Running and debugging Dart command-line applications

With IntelliJ IDEA, you can run and debug Dart command-line applications. IntelliJ IDEA supports two debugging modes:

Local debugging: in this mode, your application is started from IntelliJ IDEA and is running locally on your computer. To run or debug it, use a Dart Command Line App configuration.
Debugging a remote application: in this mode, your application is running in a remote environment, for example, in a Docker container. To debug it, use a Dart Remote Debug configuration.

Run a Dart command-line application

Open the Dart file to start the application from or select it in the Project tool window. This file must contain a main() method.
From the context menu of the selection, choose Run '<dart_file_name>'. IntelliJ IDEA generates a run/debug configuration of the type Dart Command Line App and launches your application with it.

Debug a Dart command-line application locally

Configure and set breakpoints in the Dart code.
Open the Dart file to start the application from or select it in the Project tool window. This file must contain a main() method.
From the context menu of the selection, choose Debug '<dart_file_name>'. IntelliJ IDEA generates a run/debug configuration of the type Dart Command Line App and starts a debugging session with it.
In the Debug tool window that opens, step through the program, stop and resume program execution, examine it when suspended, and so on.

Create a Dart Remote Debug run/debug configuration

On the main menu, go to Run | Edit Configurations, click and select Dart Remote Debug from the list. The Run/Debug Configuration: Dart Remote Debug opens.
In the Search Sources in field, specify the Dart project to debug if your IntelliJ IDEA project contains several Dart projects configured as content roots. Select the Dart project from the list or click and select the required folder in the dialog that opens.

Launch a remote debugging session

Start a remote Dart application with the VM options, for example, with --enable-vm-service --pause_isolates_on_start. The application starts, immediately suspends thanks to the --pause_isolates_on_start argument, and waits for the debugger to connect.
In the Run tool window, copy the URL address at which the application is running and the generated authentication token to access it.
Choose the newly created Dart Remote Debug configuration in the Select run/debug configuration list and click .
In the Connect to a Running App dialog, paste the URL address and the authentication token you copied as described above.
In the Debug tool window that opens, step through the program, stop and resume program execution, examine it when suspended, and so on.

Running and debugging Dart web applications

You can run a Dart web application in any browser, while debugging is supported only in Chrome. To run a Dart web application, open the main HTML file of your application in a browser. Debugging a Dart web application is initiated through a run configuration of the type Dart Web.

IntelliJ IDEA integrates with the webdev server tool to compile Dart code into JavaScript if necessary. For versions earlier than Dart SDK 2, the pub serve tool is used.

When you open a Dart web application in a browser, it normally starts with a built-in server URL like http://localhost:63342/project-name/web/index.html. However, the built-in server is not used to serve the application. Instead, IntelliJ IDEA automatically starts webdev server on the port specified in the Dart dialog and the browser page is redirected to the webdev server URL (like http://localhost:53322/index.html ).

The work of webdev server is logged in the dedicated Dart Webdev tool window. The tool window opens when you start running or debugging a Dart web application for the first time during the current IntelliJ IDEA session. You can stop the tool by clicking on the toolbar. When you start running or debugging again, webdev server restarts automatically.

The recommended way to debug Dart web applications is to use a Dart Web configuration. In this mode, webdev server starts with Dart DevTools enabled.

However, you can still use a JavaScript Debug configuration. See Alternative way to run and debug Dart web applications for details.

Create a Dart Web run/debug configuration:
From the main menu, select Run | Edit Configuration, click on the toolbar and select Dart Web from the list.
In the Run/Debug Configuration: Dart Web dialog that opens, specify the path to the HTML file that references the Dart code to run or debug and the port on which the webdev server will start the Dart web app.
To run your application, select the newly created Dart Web configuration from the Select run/debug configuration list on the toolbar, and click next to the list.
The browser opens at 127.0.0.1:<webdev_port>/<specified_HTML_file>.
To debug your application, set the breakpoints in the Dart code, as required. Then select the newly created Dart Web configuration from the Select run/debug configuration list on the toolbar, and click next to the list.

Alternative way to run and debug Dart web applications

Besides using a Dart Web run/debug configuration, which is the recommended workflow, with IntelliJ IDEA, you can still run and debug Dart web applications with a JavaScript Debug configuration.

Run a Dart web application

Open the HTML file with a Dart reference or select it in the Project tool window.
From the context menu of the editor or selection, select Open in Browser and choose the required browser in the list.

Create a JavaScript Debug run/debug configuration

Open the HTML file that references Dart or select the file in the Project tool window.
From the context menu, select Create '<HTML_file_name>'. The Run/Debug Configuration: JavaScript Debug dialog opens.
Specify the browser from the Chrome family to debug the application in.
The URL field already shows the URL address of the application in the format http://localhost:<built-in server port>/<project-name>/<relative path to the HTML file>. During a debugging session, the browser will be redirected from this URL to the webdev server URL.
Make sure the port in this URL address is the same as the Built-in server port on the Debugger page.

Start debugging

Configure and set breakpoints in the Dart code.
Initiate a debugging session: choose the created run configuration from the Edit configurations list on the toolbar and click . IntelliJ IDEA opens the specified URL in the chosen browser.
In the Debug tool window that opens, step through the program, stop and resume program execution, examine it when suspended, and so on.

Testing Dart applications

IntelliJ IDEA supports running and debugging Dart tests that are written using the dart test package. You can run tests on any target platform, debugging is supported only for VM tests.

You can run and debug single tests, test groups, as well as tests from entire files and folders. IntelliJ IDEA creates a run/debug configuration with the default settings and a launches the tests. You can later save this configuration for further re-use.

Run or debug a single test

Open the test file in the editor, right-click the call of the test() method, and choose Run '<test_name>' or Debug '<test_name>' from the context menu.

Run or debug a group

Open the test file in the editor, right-click the call of the group() method, and choose Run '<group_name>' or Debug '<group_name>' from the context menu.

Run or debug Dart tests from a file

In the Project tool window, select the file with the tests to run and choose Run '<file_name>' or Debug '<file_name>' from the context menu.

Run or debug Dart tests from a folder

In the Project tool window, select the folder with the tests to run and choose Run '<folder_name>' or Debug '<folder_name>' from the context menu.

Save an automatically generated default configuration

After a test session is over, choose Save <default_test_configuration_name> from the context menu of the test, test group, test file, or folder.

Run or debug tests using a previously saved run/debug configuration

Choose the required Dart Test configuration from the list on the toolbar and click or .

Configuring syntax highlighting

You can configure Dart-aware syntax highlighting according to your preferences and habits.

In the Settings/Preferences dialog Ctrl+Alt+S, go to Editor | Color Scheme | Dart.
Select the color scheme, accept the highlighting settings inherited from defaults or customize them as described in Colors and fonts.

Last modified: 26 May 2021