Automate rtl css generation with Grunt

15.01.2016

Author:

voron

Creation of RTL CSS is quite an important process in front-end, necessary to make the design comply with the RTL standards. This process invlolves the substitution of margin-left by margin-right, float: left by float: right… and so on.

Luckily, this job can be done by Grunt with the help of grunt-css-flip bundle, which creates a "reflection" of the CSS file. You can learn the basics of Grunt in the following article. So, let’s get started!

Installing and configuring grunt-css-flip:

1. Install and configure Grunt.

2. Install grunt-css-flip bundle:

npm install grunt-css-flip --save-dev.

3. Create Gruntfile.js.

Let’s analyze the following example of Gruntfile.js file:

 module.exports = function(grunt) {
  grunt.initConfig({
    pkg: grunt.file.readJSON('package.json'),
    watch: {
      css: {
        files: '**/*.css',
        tasks: ['cssflip:my_target']
      },
    },
    cssflip: {
      my_target: {
        options: {},
        files: {
          'css/styles-rtl.css': 'css/styles.css',
        }
      }
    },
    concurrent: {
      options: {
        logConcurrentOutput: true
      },
      dev: {
        tasks: ["watch:css"]
      }
    }
  });
  grunt.loadNpmTasks('grunt-contrib-watch');
  grunt.loadNpmTasks('grunt-concurrent');
  grunt.loadNpmTasks('grunt-css-flip');
  grunt.registerTask('default',['concurrent:dev']);
}

Pay attention on this part of the code

  cssflip: {
      my_target: {
        options: {},
        files: {
          'css/styles-rtl.css': 'css/styles.css',
        }
      }
    },

Files: here we set the files that should be reflected (you can specify a few files and separate them by comma). Files are defined as: ‘ rtl file name’: ‘file name for which rtl copy must be created’.

Options: here we indicate whether RTL file should be compressed or not (compress parameter, default false value), and set margins for css (indent parameter, default value and 2 hiatuses).

4. Run Grunt

From this moment, Grunt will monitor chosen CSS files (in example given it’s css/styles.css) and create the relevant reflected files.

Comments and Specifications :

Grunt-css-flip can be used together with Compass, where Compass generates CSS with sass, and Grunt monitors changes in the CSS files. If they were changed, it would run grunt-css-flip. Grunt-css-flip can be also used with other bundles, where, for instance, Grunt will validate sass/less code (grunt-scss-lint bundle). If the check was over, it would generate CSS (grunt-sass bundle), add prefixes (grunt-autoprefixer bundle) and also generate rtl CSS files (grunt-css-flip bundle).