Grunt, Less, and File Watching

Question

I'm trying to get grunt working to do something. My project looks like this:

/app
    /assets
        /components
        /stylesheets
            /less
                /file1.less
                /file2.less
                /file3.less
                /importAll.less
            /css

I want it so that when file1, file2, or file3 are saved the importAll.less file is compiled into css and put into /css/style.css. This is as far as I got.

less: {
    development: {
        options: {
            paths: ["./assets/stylesheets/less"],
            yuicompress: true
        },
        files: {
            "./assets/stylesheets/css/style.css": "./assets/stylesheets/less/importAll.less"
        }
    }
}

I'm not sure how to get the file watcher working.

Answer 1

I got it working with the following!

module.exports = function(grunt) {
    grunt.initConfig({
        less: {
            development: {
                options: {
                    paths: ["./assets/stylesheets/less"],
                    yuicompress: true
                },
                files: {
                    "./assets/stylesheets/css/style.css": "./assets/stylesheets/less/style.less"
                }
            }
        },
        watch: {
            files: "./assets/stylesheets/less/*",
            tasks: ["less"]
        }
    });
    grunt.loadNpmTasks('grunt-contrib-less');
    grunt.loadNpmTasks('grunt-contrib-watch');
};