Grunt - run task(saas,cssmin) in loop - gruntjs

Question

I am trying to implement Grunt to automate the process of CSS merging and minification. My Folder Structure:
folder1
-- sass
-- css
folder2
-- sass
-- css
folder3
-- sass
-- css
folder4
-- sass
-- css
Requirement: Individually, the grunt task is running properly on each project when it is triggering on file Save from eclipse. But, what I want is to execute the minification process for all folders by issuing grunt command i.e. when I type "grunt" in cmd, it should loop through the folder to generate minified css for each. Currently, it is generating the css for the last folder in each iteration as initconfig is inside the loop.
Simplified version of Gruntfile.js(carrying only relevant code):
module.exports = function(grunt) {
var tasks = [
'grunt-contrib-cssmin','grunt-sass'
];
tasks.forEach( function ( task ) {
grunt.loadNpmTasks( task );
});
var folder =['folder1', 'folder2', 'folder3', 'folder4'];
var source;
var csspath;
var destination;
for (var i = 0; i < folder.length; i ++ ) {
source=folder[i] + '/sass/*.scss';
csspath=folder[i] + '/css/';
destination=csspath + 'combined-styles.css';
grunt.initConfig({
config: {
destination: destination
},
sass: {
dist: {
files: {
'<%= config.destination %>' : [source]
}
},
},
cssmin: {
target: {
files: [{
expand: true,
cwd: csspath,
src: ['combined-styles.css'],
dest: csspath,
ext: '.min.css'
}]
}
}
});
grunt.task.registerTask(folder[i], ['sass','cssmin']);
}
grunt.task.registerTask('default', folder);
};
Any help would be highly appreciated, Thanks.

Answer 1

I was able to fix the issue. Following are the steps:
Initialized sass and cssmin array
Changed my sass task configuration from
files: {
'<%= config.destination %>' : [source]
}
to
files: [{
expand: true,
cwd: scsspath,
src: [source],
dest: csspath,
ext: '.css'
}]
(similar to cssmin)
Added value to array sass and cssmin for each folder
Assigned the sass and cssmin array to sass and cssmin task respectively using grunt.config.set:
grunt.config.set("sass", sass);
grunt.config.set("cssmin", cssmin);
Register task "sass" and "cssmin"
grunt.task.registerTask('default', ['sass','cssmin']);
Correct Gruntfile.js:
module.exports = function(grunt) {
var tasks = [
'grunt-contrib-cssmin','grunt-sass'
];
tasks.forEach( function ( task ) {
grunt.loadNpmTasks( task );
});
var folder =['folder1', 'folder2', 'folder3', 'folder4'];
var source,csspath,scsspath;
var sass={};
var cssmin={};
for (var i = 0; i < folder.length; i ++ ) {
scsspath=folder[i] + '/sass/';
source='*.scss';
csspath=folder[i] + '/css/';
sass["folder"+i]= {
files: [{
expand: true,
cwd: scsspath,
src: [source],
dest: csspath,
ext: '.css'
}]
};
cssmin["folder"+i]= {
files: [{
expand: true,
cwd: csspath,
src: ['combined-styles.css'],
dest: csspath,
ext: '.min.css'
}]
};
}
grunt.config.set("sass", sass);
grunt.config.set("cssmin", cssmin);
grunt.task.registerTask('default', ['sass','cssmin']);
};