作用:

可以用来将数据组合成树形的数据,可以像操作单独的对象一样去操作整个树形结构

树是相对复杂的数据,使用组合模式去封装树形的组件,是很重要的,可以对外暴露很多树的操作方法

示例:

        //一个树型的对象数据class Organ {constructor(label, value, parentName) {this.label = labelthis.value = valuethis.parentName = parentNamethis.childRen = []}}//新增元素Organ.prototype.addChildRen = function () {let arr = Array.from(arguments)arr.forEach(item => {this.childRen.push(item)this.flatList.push([this.value,item.value])})this.changeTreeNodeList()}//删除某个元素,其子节点也都会被一并删除Organ.prototype.removeChildRen = function (nodeValue) {let index = this.childRen.findIndex(val => val.value === nodeValue)this.childRen.splice(index,1)let arr = this.flatList.map(item=>{if(!item.includes(nodeValue)){return item}})this.flatList = arr.filter(item => item !== undefined)this.changeTreeNodeList()}//过滤生成树的各条节点路线Organ.prototype.changeTreeNodeList = function(){this.treeNodeList.length = 0this.flatList.forEach(item1=>{let obj = this.flatList.find(item2 => item2[item2.length-1] === item1[0])if(obj){this.treeNodeList.push([... new Set([].concat(obj).concat(item1))])}})}Organ.prototype.flatList = []Organ.prototype.treeNodeList = []//创建父级组织const jituanjun1 = new Organ('第一集团军','jituanjun1',false)//创建子级组织const hechenglv1 = new Organ('合成1旅','hechenglv1','jituanjun1')const hechenglv2 = new Organ('合成2旅', 'hechenglv2','jituanjun1')//子级组织加入父级组织jituanjun1.addChildRen(hechenglv1, hechenglv2)//下面操作重复上面的操作const bubingying1 = new Organ('步兵1营', 'bubingying1','hechenglv1')const bubingying2 = new Organ('步兵2营', 'bubingying2','hechenglv1')hechenglv1.addChildRen(bubingying1,bubingying2)const bubingying3 = new Organ('步兵3营', 'bubingying3','hechenglv2')const bubingying4 = new Organ('步兵4营', 'bubingying4','hechenglv2')hechenglv2.addChildRen(bubingying3,bubingying4)const bubingying5 = new Organ('步兵5营', 'bubingying5','hechenglv2')hechenglv2.addChildRen(bubingying5)//撤编hechenglv2.removeChildRen('bubingying4')console.log(jituanjun1,'第一集团军编制')console.log(jituanjun1.treeNodeList,'树的所有完整节点流向')