WebStorm 9.0.2 Web Help

Transpiling SASS, LESS, and SCSS to CSS

Sass, LESS, and SCSS code is not processed by browsers that work with CSS code. Therefore to be executed, Sass, LESS, or SCSS code has to be translated into CSS. This operation is referred to as transpilation and the tools that perform it are called transpilers.

WebStorm supports integration with transpiler tools that translate Sass, LESS, and SCSS code into CSS.

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:

Installing the SASS/SCSS transpiler

  1. Download and install Ruby.
  2. Specify a path variable for the folder where the Ruby executable file and the gem.bat file are stored. This lets you launch Ruby and Gem Manager from any folder and ensures that Ruby is successfully launched during transpilation.
  3. Type one of the following commands at the command line prompt:
    gem install sass
    or
    gem install scss

    The tool is installed to the folder where Ruby executable file and the gem.bat file are stored.

Installing the LESS transpiler

The easiest way to install the LESS transpiler is to use the Node Package Manager (npm), which is a part of Node.js.

Depending on the desired location of the LESS transpiler executable file, choose one of the following methods:

  • Install the transpiler globally at the WebStorm level so it can be used in any WebStorm project.
  • Install the transpiler in a specific project and thus restrict its use to this project.
  • Install the transpiler in a project as a development dependency.

In either installation mode, make sure that the parent folder of the LESS transpiler is added to the PATH variable. This enables you to launch the transpiler from any folder.

WebStorm provides user interface both for global and project installation as well as supports installation through the command line.

Installing the LESS transpiler globally

  1. Run the installation from the command line in the global mode:
    1. Launch the embedded Terminal by hovering your mouse pointer over show_tool_window_bars in the lower left corner of WebStorm and choosing Terminal from the menu (see Working with Embedded Local Terminal for details).
    2. Switch to the directory where NPM is stored or define a PATH variable for it so it is available from any folder, see Installing NodeJs.
    3. Type the following command at the command line prompt:
      npm install -g less

      For more details on the NPM operation modes, see npm documentation. For more information about installing the LESS transpiler, see https://npmjs.org/package/less.

  2. Run NPM from WebStorm using the Node.js and NPM page of the Settings dialog box.
    1. Open the Settings dialog box by choosing File | Settings or pressing Ctrl+Alt+S and click Node.js and NPM under Languages&Frameworks.
    2. On the Node.js and NPM page that opens, the Packages area shows all the Node.js-dependent packages that are currently installed on your computer, both at the global and at the project level. Click add.
    3. In the Available Packages dialog box that opens, select the required package to install.
    4. Select the Options check box and type -g in the text box next to it.
    5. Optionally specify the product version and click Install Package to start installation.

Installing the LESS transpiler in a project

  • Run the installation from the command line:
    1. Launch the embedded Terminal by hovering your mouse pointer over show_tool_window_bars in the lower left corner of WebStorm and choosing Terminal from the menu (see Working with Embedded Local Terminal for details).
    2. Switch to the project root folder and type the following command at the command line prompt:
      npm install less
  • Run NPM from WebStorm using the Node.js and NPM page of the Settings dialog box.
    1. Open the project settings by choosing File | Settings or pressing Ctrl+Alt+S, see Accessing Settings for details. Then click Node.js and NPM under the Languages & Frameworks node.
    2. On the Node.js and NPM page that opens, the Packages area shows all the Node.js-dependent packages that are currently installed on your computer, both at the global and at the project level. Click add.
    3. In the Available Packages dialog box that opens, select the required package.
    4. Optionally specify the product version and click Install Package to start installation.

Creating a File Watcher

  1. Make sure the File Watchers plugin is enabled. The plugin is bundled with WebStorm and activated by default. If it is not, enable the plugin. See Enabling and Disabling Plugins for details.
  2. 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.
  3. Click the Add button new.png or press Alt+Insert. Depending on the tool you are going to use, choose the appropriate predefined template from the pop-up list:
    • LESS
    • Sass
    • SCSS
  4. In the Program text box, specify the path to the compiler executable file or archive depending on the chosen predefined template.
    • lessc.cmd for LESS If you installed the tool through the Node Package Manager, WebStorm locates the required file itself at <node.js_home>/node_modules/bin/lessc.cmd and fills in the field automatically. Otherwise, type the path manually or click the Browse button browseButton.png and choose the file location in the dialog box that opens.
    • sass.bat for SASS
    • scss.bat for SCSS

    If you installed the Sass and SCSS tools through Ruby, WebStorm locates the required files itself at <ruby_home>/bin/sass.bat <ruby_home>/bin/scss.bat respectively and fills in the field automatically. Otherwise, type the path manually or click the Browse button browseButton.png and choose the file location in the dialog box that opens.

  5. Proceed as described on page Using File Watchers.

Transpiling the code

When you open a TypeScript 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).

WebStorm creates a separate file with the generated output. The file has the name of the source Sass, LESS, or SCSS file and the extension css. The location of the generated files is defined in the Output paths to refresh text box of the New Watcher dialog. However, in the Project Tree, they are shown under the source file which is now displayed as a node.

See Also

Last modified: 11 December 2014
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