gulp watch 执行出错（watchtaskisnot啊fucntion）

Question

var gulp=require("gulp");var uglify=require("gulp-uglify");gulp.task("uglify",function(){ gulp.src("js/*.js").pipe(uglify()).pipe(gulp.dest("js-uglify"));})gulp.task('auto1',function(){    gulp.watch("js/*.js",['uglify']);})运行结果