组合模式（文件夹的扫描）

class Folder {
    constructor(name){
        this.name = name;
        this.files = [];
        this.parent= null;//添加父类
    }
    add(file){
        file.parent = this;//设置父对象
        this.files.push(file)
    }
    scan(){
        console.log('开始扫描文件夹：'+this.name)
        for(var i = 0;i<this.files.length;i++){
            this.files[i].scan()
        }
    }
    remove(){
        if(!this.parent){ //根节点或树外节点
            return 
        }
        for(var files = this.parent.files,l = files.length-1;l>=0;l--){ //删除当前节点
            var file =files[l]
            if(file===this){
                files.splice(l,1)
            }
        }
    }
}
class File {
    constructor(name){
        this.name = name
        this.parent = null
    }
    add(){
        throw new Error('文件下不可新增')
    }
    scan(){
        console.log('开始扫描文件：'+this.name)
    }
    remove(){
        if(!this.parent){
            return
        }
        for(var files = this.parent.files,l = files.length-1;l>=0;l--){
            var file =files[l]
            if(file===this){
                files.splice(l,1)
            }
        }
    }
}
var folder = new Folder('学习资料');
var folder1 = new Folder('JavaScript');
var folder2 = new Folder('jquery')
var file1= new File('JavaScript设计模式与开发实践')
var file2 =new File('精通Jquery')
var file3= new File('重构与模式')
folder1.add(file1)
folder2.add(file2)
folder.add(folder1)
folder.add(folder2)
folder.add(file3)
var folder3 = new Folder('NodeJs')
var file4 = new File('深入浅出Nodejs')
folder3.add(file4)
var file5 = new File('JavaScript语言精髓与编程实践')
folder.add(folder3)
folder.add(file5)
folder1.remove()
folder.scan()

输出结果