How can I make Grunt.js imagemin to track *any* folder and possibly store images in one place?

Question

I'm relatively new to Grunt.js, setting up is quiet easy, but now I have 2 issues: 1) First, how do you track any folder inside a given sources folder? For example, images folder may itself contain images, as well as folders with images and folders with folders with images etc. 2) Is there a way to watch for images in it's primary (build) folder? Without any forever loop...

Here's my current config:

module.exports = function(grunt) {
grunt.initConfig({
    jsDir: 'sources/js/',
    jsDistDir: 'public/js/',
    cssDir: 'sources/css/',
    cssDistDir: 'public/css/',
    concat: {
        js: {
            src: ['<%=jsDir%>*.js'],
            dest: '<%=jsDistDir%>javascript.js'
        },
        css: {
            src: ['<%=cssDir%>*.css'],
            dest: '<%=cssDistDir%>styles.css'
        }
    },
    min: {
        dist: {
            src: ['<%= concat.js.dest %>'],
            dest: '<%=jsDistDir%>javascript.js'
        }
    },
    cssmin: {
        dist: {
            src: ['<%= concat.css.dest %>'],
            dest: '<%=cssDistDir%>styles.css'
        }
    },
    imagemin: {
        dynamic: {
            files: [{
                expand: true,
                cwd: 'sources/images/',
                src: ['**/*.{png,jpg,gif}'],
                dest: 'public/images/'
            }]
        }
    },
    watch: {
        min: {
            files: ['<%=jsDir%>*.js'],
            tasks: ['concat:js', 'min']
        },
        cssmin: {
            files: ['<%=cssDir%>*.css'],
            tasks: ['concat:css', 'cssmin']
        },
        imagemin: {
            files: ['sources/images/**/*.{png,jpg,gif}'],
            tasks: ['imagemin']
        }
    }
});

grunt.loadNpmTasks('grunt-contrib-concat');
grunt.loadNpmTasks('grunt-yui-compressor');
grunt.loadNpmTasks('grunt-contrib-imagemin');
grunt.loadNpmTasks('grunt-contrib-watch');

grunt.registerTask('default', [
    'concat',
    'min',
    'cssmin',
    'imagemin',
    'watch'
]);
};

Thanks!

Answer 1

Question 1):

The Expression **/* does exactly this. (see imagemin > dynamic > files > src). Inside the concat section you could do something like src: ['<%=jsDir%>**/*.js'],

Question 2): Use a a watch task:

Install: npm install grunt-contrib-watch --save-dev

(--save-dev means write dependency to package.json file)

Configuration in Gruntfile.js:

(function () {
    'use strict';
}());

module.exports = function(grunt) {
    require('load-grunt-tasks')(grunt);  // auto load grunt tasks
    var globalConfig = {
        jsPath: 'js/',
        cssPath: 'css/',
        scssPath: 'scss/',
    };

    grunt.initConfig({
        globalConfig: globalConfig,
        pkg: grunt.file.readJSON('package.json'),

        concat: {
            // conf goes here
        },
        // your other tasks go here
        imagemin: {
            // conf goes here
        },

        watch: {
            dev:{
                files: ['<%= globalConfig.jsPath %>_*.js', '<%= globalConfig.scssPath %>**/*.scss'],
                tasks: ['concat','imagemin', 'yourothertasks']
            }
        }
    });

    grunt.registerTask('default', ['concat', 'imagemin', 'yourothertasks', 'watch:dev']);
};