Grunt: Watch multiple files, Compile only Changed

It's easy to complier JS that is changed after setting gunt-contrib-watch.
But how to watch multiple files but compile only Changed ?

This is a sample [Grunt watch] & [ Google closure] for you :

*Gruntfile.js

module.exports = function(grunt) {
    grunt.initConfig({
        closure-compiler: {
                    other: {
                closurePath:'/Library/closure/',
                js: ['js/*.js'
                ],
                jsOutputFile: 'js/dist/*.js',
                noreport: true,
                options: {
                    compilation_level: 'SIMPLE_OPTIMIZATIONS',
                    //compilation_level: 'ADVANCED_OPTIMIZATIONS',
                    warning_level:"DEFAULT",
                    define: [
                    '"DEBUG=false"',
                    '"UI_DELAY=500"'
                    ],
                }
            }
        },
        watch: {
            other: {
                files: ['js/*.js'],
                tasks: ['closure-compiler:other'],
                options: {
                    debounceDelay: 500,
                    spawn: false,
                },  
            }
        } 
  });
    grunt.loadNpmTasks('grunt-closure-compiler');
    grunt.loadNpmTasks('grunt-contrib-watch');
    grunt.event.on('watch', function(action, filepath, target) {
    //change the source and destination in the uglify task at run time so that it affects the changed file only
        var destFilePath = filepath.replace(/^js\/(.+)\.js$/, 'js/dist/$1.min.js');
        grunt.log.write(destFilePath);
        grunt.config('closure-compiler.other.js', filepath);
        grunt.config('closure-compiler.other.jsOutputFile', destFilePath);
    });
};