SOURCE

var Folder = function(name){
			this.name = name;
			this.parent = null;
			this.files = [];
		}
		Folder.prototype.add = function(file){
			file.parent = this;
			this.files.push(file)
		}
		Folder.prototype.scan = function(){
			console.log('begin scan')
			for(var i = 0,file,files = this.files;file = files[i++];){
				file.scan()
			}
		}
		Folder.prototype.remove = function(){
			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 File = function(name){
			this.name = name;
			this.parent = null;
		}
		File.prototype.add = function(){
			throw new Error('throw add')
		}
		File.prototype.scan = function(){
			console.log('begin scan'+this.name)
		}
		File.prototype.remove = function(){
			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 file1 = new Folder('深入浅出Node')

		folder1.add(new File("JavaScript设计模式与开发实践"))
		folder.add(folder1)
		folder.add(file1)

		folder1.remove()
		console.log(111)
		folder.scan()