gulp-sass 5 does not have a default Sass compiler; 是什么问题？

const {src, dest, series, watch} = require('gulp')
const del = require('del')

//gulp-uglify => plugins.uglify = require('gulp-uglify')
const plugins = require('gulp-load-plugins')()

//压缩js uglify
function js(cb){
src('js/*.js')
// 下一个处理环节
.pipe(plugins.uglify())
.pipe(dest('./dist/js'))
cb()
}

//对sccs/less 编译，输出css文件
function css(cb){
src('css/*.scss')
.pipe(plugins.sass({outputStyle: 'compressed'}))
.pipe(plugins.autoprefixer({
cascade: false,
remove: false
}))
.pipe(dest('./dist/css'))

cb()
}

//监听这些文件变化
function watcher(){
watch('js/*.js', js)
watch('css/*.scss', js)
}

//删除dist目录的内容
function clean(cb){
del('./dist')
cb()
}

exports.scripts = js
exports.styles = css
exports.clean = clean
exports.default = function(){
clean,
js,
css,
watcher
}

wanglimindeMacBook-Air:demo1 wanglimin$ npx gulp styles

[07:37:06] Using gulpfile ~/Desktop/大前端练习/demo1/gulpfile.js

[07:37:06] Starting 'styles'...

Error in plugin "gulp-sass"

Message:

gulp-sass 5 does not have a default Sass compiler; please set one yourself.

Both the `sass` and `node-sass` packages are permitted.

For example, in your gulpfile:

  var sass = require('gulp-sass')(require('sass'));

[07:37:06] The following tasks did not complete: styles

[07:37:06] Did you forget to signal async completion?

请教一下老师上面的提示是什么问题？

尝试过的解决方式：

我直接把 “

  var sass = require('gulp-sass')(require('sass'));

”

复制粘贴到 gulpfile.js 

再运行 nxp gulp scripts 爆出来下面的错误提示

谢谢！

wanglimindeMacBook-Air:demo1 wanglimin$ npx gulp styles

{ Error: Cannot find module 'sass'

    at Function.Module._resolveFilename (internal/modules/cjs/loader.js:636:15)

    at Function.Module._load (internal/modules/cjs/loader.js:562:25)

    at Module.require (internal/modules/cjs/loader.js:690:17)

    at require (internal/modules/cjs/helpers.js:25:18)

    at Object.<anonymous> (/Users/wanglimin/Desktop/大前端练习/demo1/gulpfile.js:4:33)

    at Module._compile (internal/modules/cjs/loader.js:776:30)

    at Object.Module._extensions..js (internal/modules/cjs/loader.js:787:10)

    at Module.load (internal/modules/cjs/loader.js:653:32)

    at tryModuleLoad (internal/modules/cjs/loader.js:593:12)

    at Function.Module._load (internal/modules/cjs/loader.js:585:3) code: 'MODULE_NOT_FOUND' }