组合模式

const Folder = function (folder) {
    this.folder = folder
    this.list = []
}

Folder.prototype.add = function (res) {
    this.list.push(res)
}

Folder.prototype.scan = function () {
    console.log('扫描文件夹', this.folder)
    for (let i = 0; i < this.list.length; i++) {
        this.list[i].scan()
    }
}

const File = function (file) {
    this.file = file
}
File.prototype.scan = function () {
    console.log('开始扫描文件', this.file)
}

let rootFolder = new Folder('root')
let htmlFolder = new Folder('html')
let cssFolder = new Folder('css')
let jsFolder = new Folder('js')

let html4 = new File('html4')
let html5 = new File('html5')
let css2 = new File('css2')
let css3 = new File('css3')
let es5 = new File('es5')
let es6 = new File('es6')

rootFolder.add(htmlFolder)
rootFolder.add(cssFolder)
rootFolder.add(jsFolder)

htmlFolder.add(html4)
htmlFolder.add(html5)
cssFolder.add(css2)
cssFolder.add(css3)
jsFolder.add(es5)
jsFolder.add(es6)

rootFolder.scan()