我有一个grunt文件,但我在编译时遇到问题.当我观看它似乎运行正常但不产生任何文件.

我错过了什么？

module.exports = function(grunt) {
    grunt.initConfig({
        pngmin: {
            compile: {
                options: {
                    ext: '.png',force: true,speed: 3,colors: 200
                },files: [{
                    expand: true,// required option
                    src: ['**/*.png'],cwd: 'public/images/src/',// required option
                    dest: 'public/images/dist/'
                }]
            }
        },sass: {
            dist: {
                files: [
                    {
                        expand: true,cwd: "public/sass",src: ["**/*.sass"],dest: "public/stylesheets",ext: ".css"
                    }
                ]
            }
        },watch: {
            css: {
                files: '**/*.scss',tasks: ['sass']
            }
        }
    });


    grunt.loadNpmTasks('grunt-contrib-sass');
    grunt.loadNpmTasks('grunt-contrib-watch');
    grunt.loadNpmTasks('grunt-pngmin');
    grunt.registerTask('default',['pngmin','watch','sass']);

};