Automated sass compression for VuFind's grunt file

css.js

grunt.registerMultiTask('css', function (arg1, arg2) {
  var fs = require('fs')
    , path = require('path')
    , options = (arguments.length > 0 && this.data[arg1] && this.data[arg1].options)
      ? this.data[arg1].options
      : this.data.dist.options
    , theme = (arguments.length > 1) ? arg2 : null
    , themeFolder = this.data.options.themeFolder || 'themes'
    , themeList = fs.readdirSync(path.resolve(themeFolder))
    , sassConfig = {}
    ;

  var inheritance = {};
  for (var i in themeList) {
    if (theme && themeList[i] !== theme) {
      continue;
    }
    var config = fs.readFileSync(path.join(themeFolder, themeList[i], 'theme.config.php'), 'UTF-8');
    inheritance[themeList[i]] = config.toLowerCase().replace(/[\s']/g, '').match(/extends=>(\w+)/)[1];
  }

  for (var i in themeList) {
    var sassDir = path.join(themeFolder, themeList[i], 'sass');
    var cssDir = path.join(themeFolder, themeList[i], 'css');
    try {
      fs.statSync(sassDir);
      // Build load path
      var loadPath = [];
      var curr = themeList[i];
      while (inheritance[curr] != 'root') {
        loadPath.unshift(path.join(themeFolder, inheritance[curr], 'sass'));
        curr = inheritance[curr];
      }
      if (loadPath.length > 0) {
        options.loadPath = loadPath;
      }
      // Compile
      var files = {};
      files[path.join(cssDir, 'compiled.css')] = path.join(sassDir, themeList[i].replace(/\d/g, '')+'.scss');
      sassConfig[themeList[i]] = {
        options: options,
        files: files
      };
    } catch (err) {
      // silently suppress thrown errors when no sass sources exist in a theme
    }
  }

  grunt.config.set('sass', sassConfig);
  grunt.task.run('sass');
  grunt.task.run('replace');
});

Attempts to discover all themes with sass, build their inheritance paths, and compile their sass automatically. Call with grunt css. Change task name at top if you wish.