Transpiling Sass, Less, and SCSS to CSS

On this page:

• Introduction
• Installing the Sass/SCSS transpiler
• Installing the Less transpiler
  • Installing the Less transpiler globally
  • Installing the Less transpiler in a project
• Creating a file watcher
• Transpiling the code

Introduction

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.

PhpStorm supports integration with transpiler tools that translate Sass, Less, and SCSS code into CSS.

In PhpStorm, transpiler configurations are called File Watchers. For each supported transpiler, PhpStorm provides a predefined File Watcher template. Predefined File Watcher templates are available at the PhpStorm 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.

Installing the Sass/SCSS transpiler

Sass and SCSS transpilers are managed through the Ruby Gem manager.

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. See Installing and Removing External Software Using Node Package Manager for details.

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

• Install the transpiler globally at the PhpStorm level so it can be used in any PhpStorm 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.

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

Installing the Less transpiler globally

Global installation makes a transpiler available at the PhpStorm level so it can be used in any PhpStorm project. Moreover, during installation the parent folder of the transpiler is automatically added to the PATH variable, which enables you to launch the transpiler from any folder. To install the transpiler globally, do one of the following:

• Run the installation from the command line in the global mode:
  1. Launch the embedded Terminal by hovering your mouse pointer over in the lower left corner of PhpStorm 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

     The -g key makes the transpiler run in the global mode. Because the installation is performed through NPM, the Less transpiler is installed in the npm folder. Make sure this parent folder is added to the PATH variable. This enables you to launch the transpiler from any folder.

     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.

• Run NPM from PhpStorm using the Node.js and NPM page of the Settings dialog box.
  1. Open the Settings / Preferences Dialog by pressing Ctrl+Alt+S or by choosing File | Settings for Windows and Linux or PhpStorm | Preferences for OS X, 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 .
  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

Installing a transpiler in a specific project restricts its use to this project. To run project installation, do one of the following:

• Run the installation from the command line:
  1. Launch the embedded Terminal by hovering your mouse pointer over in the lower left corner of PhpStorm 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 PhpStorm using the Node.js and NPM page of the Settings dialog box.
  1. Open the Settings / Preferences Dialog by pressing Ctrl+Alt+S or by choosing File | Settings for Windows and Linux or PhpStorm | Preferences for OS X, 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 .
  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.

Project level installation is helpful and reliable in template-based projects of the type Node Boilerplate or Node.js Express, which already have the node_modules folder. The latter is important because NPM installs the Less transpiler in a node_modules folder. If your project already contains such folder, the Less transpiler is installed there.

Projects of other types or empty projects may not have a node_modules folder. In this case npm goes upwards in the folder tree and installs the Less transpiler in the first detected node_modules folder. Keep in mind that this detected node_modules folder may be outside your current project root.

Finally, if no node_modules folder is detected in the folder tree either, the folder is created right under the current project root and the Less transpiler is installed there.

In either case, 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.

Creating a file watcher

PhpStorm provides a common procedure and user interface for creating File Watchers of all types. The only difference is in the predefined templates you choose in each case.

1. Make sure the File Watchers plugin is enabled. The plugin is bundled with PhpStorm 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 Settings/Preferences dialog box by choosing File | Settings for Windows and Linux or PhpStorm | Preferences for OS X 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 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, PhpStorm 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 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, PhpStorm 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 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, PhpStorm checks whether an applicable file watcher is available in the current project. If such file watcher is configured but disabled, PhpStorm 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, PhpStorm 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 PhpStorm (upon frame deactivation).

PhpStorm 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.