In WebStorm, transpiler configurations are called File Watchers. For each supported transpiler, WebStorm provides a predefined File Watcher template. Predefined File Watcher templates are available at the WebStorm level. To run a transpiler against your project files, you need to create a project-specific File Watcher based on the relevant template, at least, specify the path to the transpiler to use on your machine.
On this page:
Creating a File Watcher
- To start creating a File Watcher, open the Project Settings by choosing File | Settings on the main menu, and then click File Watchers under the Tools node. The File Watchers page that opens, shows the list of File Watchers that are already configured in the project.
- Click the Add button or press Alt+Insert and choose the Dart2JS predefined template from the pop-up list.
In the Program text box, specify the path to the
dart2js.batfile. Type the path manually or click the Browse button and choose the file location in the dialog box that opens. The default location is
- Proceed as described on page Using File Watchers.
Transpiling the Dart code
When you open a Dart file, WebStorm checks whether an applicable file watcher is available in the current project. If such file watcher is configured but disabled, WebStorm displays a pop-up window that informs you about the configured file watcher and suggests to enable it.
If an applicable file watcher is configured and enabled in the current project, WebStorm starts it automatically upon the event specified in the New Watcher dialog.
- If the Immediate file synchronization check box is selected, the File Watcher is invoked as soon as any changes are made to the source code.
- If the Immediate file synchronization check box is cleared, the File Watcher is started upon save ( File | Save All , Ctrl+S) or when you move focus from WebStorm (upon frame deactivation).
The transpiler stores the generated output in a separate file. The file has the name of the source Dart file and the extension
depending on the transpiler type. The location of the generated files is defined in the Output paths to refresh text box
of the New Watcher dialog. Based on this setting, WebStorm detects the transpiler output.