gulp watch 监听修改了哪个文件

var Asset = {
    js: 'src/*.js',
    less: 'dev/*.less',
    static: [
        'src/*.html',
        'src/*.css',
        'src/*.png',
        'src/*.gif',
        'src/*.json',
    ]
};
gulp.task('less', function () {
    return gulp.src(Asset.less)
        .pipe(less())
        .pipe(header(banner, {
            pkg: pkg
        }))
        .pipe(gulp.dest('src/'))
        .pipe(cssmin())
        .pipe(header(banner, {
            pkg: pkg
        }))
        .pipe(gulp.dest('dist/'))
});
gulp.task('watch', ['less'], function () {
    gulp.watch(Asset.less, ['less']);
});