The code of gulpfile.js is as follows

var gulp = require('gulp');
var $ = require('gulp-load-plugins')();//这样就可以直接引用$变量，不需要声明
var open = require('open');
// const gulp = require('gulp');
// const imagemin = require('gulp-imagemin');

var app = {
    srcPath:'src/',
    devPath:'build/',
    prdPath:'dist/'
};

//放置依赖
gulp.task('lib',function () {
    gulp.src('bower_components/**/*.js')
        .pipe(gulp.dest(app.devPath + 'vendor'))
        .pipe(gulp.dest(app.prdPath + 'vendor'))
        .pipe($.connect.reload());
});

gulp.task('html',function () {
gulp.src(app.srcPath + '**/*.html')
    .pipe(gulp.dest(app.devPath))
    .pipe(gulp.dest(app.prdPath))
    .pipe($.connect.reload());
});

gulp.task('json',function () {
    gulp.src(app.srcPath + 'data/**/*.json')
        .pipe(gulp.dest(app.devPath + 'data'))
        .pipe(gulp.dest(app.prdPath + 'data'))
        .pipe($.connect.reload());
});

gulp.task('less',function () {
    gulp.src(app.srcPath + 'style/index.less')
        .pipe($.less())
        .pipe(gulp.dest(app.devPath + 'css'))
        .pipe($.cssmin())//压缩
        .pipe(gulp.dest(app.prdPath + 'css'))
        .pipe($.connect.reload());
});

gulp.task('js',function () {
    gulp.src(app.srcPath + 'script/**/*.js')
        .pipe($.concat('index.js'))
        .pipe(gulp.dest(app.devPath + 'js'))
        .pipe($.uglify())
        .pipe(gulp.dest(app.prdPath + 'js'))
        .pipe($.connect.reload());
});

gulp.task('image',function () {
    gulp.src(app.srcPath + 'image/**/*')
        .pipe(gulp.dest(app.devPath + 'image'))
        .pipe($.imagemin())
        .pipe(gulp.dest(app.prdPath + 'image'))
        .pipe($.connect.reload());
});

gulp.task('build',['image','js','less','json','html','lib']);

// gulp.task('clean',function () {
//     gulp.src([app.devPath,app.prdPath])
//         .pipe($.clean());
// });

gulp.task('serve',['build'],function () {
    $.connect.server({
        root:'./',
        livereload:true,
        port:3000
    });
    open('http://localhost:3000');
});

gulp.task('watch',function () {
    gulp.watch('bower_components/**/*',['lib']);
    gulp.watch(app.srcPath + '**/*.html',['html']);
    gulp.watch(app.srcPath + 'data/**/*.json',['json']);
    gulp.watch(app.srcPath + 'style/**/*.less',['less']);
    gulp.watch(app.srcPath + 'script/**/*.js',['js']);
    gulp.watch(app.srcPath + 'image/**/*',['image']);
});


gulp.task('default',['watch','serve']);//默认任务

Is there something wrong with my server configuration?
Using Firefox browser. . It should be the latest version. . Please help
The previous problem has not been solved yet, that imagemin cannot compress the image, I wrote it in another question

Try to change the root of the server to [app.srcPath]. The index page can be opened, but it cannot be refreshed automatically

There is another error. . . . The port opened by the server is also incorrect. .