programatically building a grunt tasks options

sass.js

module.exports = function(grunt) {

    var pkg = grunt.file.readJSON('package.json');

    var config = {
        options: {
            includePaths: [
                '<%=wpThemeDir%>/<%= wpParentThemeDir %>/sass/partials/'
            ]
        },
        dist: {
            files: []
        }
    };

    var configs = [];
    configs['all'] = JSON.parse(JSON.stringify(config));

    for (var key in pkg.themes) {
        var taskName = key;
        var theme = pkg.themes[key];

        // clone config object
        configs[taskName] = JSON.parse(JSON.stringify(config));

        configs[taskName].dist.files.push({
            expand: true,
            flatten: true,
            ext: '.css',
            src: '<%=wpThemeDir%>/' + theme + '/sass/*.scss',
            dest: '<%=wpThemeDir%>/' + theme + '/css/'
        });

        // Add to the all task
        configs['all'].dist.files.push(configs[taskName].dist.files);
    };

    grunt.registerTask('wired_sass', function(theme) {

        if (arguments.length === 0) {
            grunt.config('sass', configs['all']);
        } else {
            grunt.config('sass', configs[theme]);
        }

        grunt.task.run('sass');

    });

};