动态树形菜单的几种递归写法小结

vue递归方法实现:

VUE中递归算法实现树形菜单的写法:

<template>
    <div>
        <!-- 父组件将数据传入子组件 -->
        <tree :msg='msg' />
    </div>
</template>

<script>

export default {  
    data (){  //模拟数据
        return{
            n:0,
            msg: [{name:'北京',
                    sub:[{name:'东城区',
                    sub:[
                        {name:'朝阳区'}
                    ]                 
                    },{name:'西城区',
                        sub:[
                            {name:'关虎屯'}
                        ]
                    
                    },{name:'南城区'},{name:'北城区'}]
                    }
                    ,{
                    name:'广东',
                    sub:[{name:'广州',
                        sub:[{name:'越秀区'},{name:'白云区'},{name:'海珠区'}]
                        },
                        {name:'深圳',
                        sub:[{name:'蛇口区'},{name:'保安区'},{name:'盐田区'}]
                        },
                    ]
                    },{
                    name:'湖北',
                    sub:[{name:'武汉',
                        sub:[{name:'江夏区'},{name:"洪山区"},{name:'江汉区'}]
                        },
                        {name:'天门市',
                        sub:[{name:'精灵'},{name:"小班"},{name:'打扮'}]
                        }]
                    }],
        }
    },
    // 注册父组件
    components: {
        tree:{
            name:'gs',//递归的构造函数名

            //父组件模板,相当于构造函数return的值
            template:`
            <ul>
                <li v-for="(v,i) in msg" :key=i @click.stop.self='n=i'>  //第一层的数据,点击之后,子集菜单会展开,其他子集菜单会关闭
                     {{v.name}} 
                     
                     <gs :msg=v.sub  v-if="i==n"/>//将下一层数据传入构造函数,进行调用,形成递归,相当于自己调用自己,这一步是最关键的一步,
                </li>
            </ul> 
            `,
            props: ['msg'],//接受父组件传的值
            data(){
                return{
                    n:0  //默认展开的菜单下标
                }
            }
        },
    }
}
</script>

方法二:

APP.vue

<template>
  <div id="app">
    <Home :items="items"></Home>
  </div>
</template>

<script>
import Home from "./components/Home.vue";

export default {
  name: "App",
  data() {
    return {
      items: [
        {
          name: "IT互联网",
          child: [
            {
              name: "编辑语言",
              child: [
                { name: "java" },
                { name: "c#/ .net" },
                { name: "python" },
              ],
            },
            {
              name: "前端开发",
              child: [{ name: "jq" }, { name: "vue " }, { name: "react " }],
            },
            {
              name: "移动开发",
              child: [{ name: " android开发" }, { name: "IOS开发" }],
            },
            {
              name: "游戏开发",
              child: [
                { name: " phaser游戏开发" },
                { name: "webGL游戏开发", child: [{ name: "3D游戏" }] },
              ],
            },
          ],
        },
      ],
    };
  },
  components: {
    Home,
  },
};
</script>

<style>
#app {
  font-family: Avenir, Helvetica, Arial, sans-serif;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-align: center;
  color: #2c3e50;
  margin-top: 60px;
}
</style>

Home.vue

<template>
  <div class="lists">
    <Item v-for="(v, i) in items" :key="i" :item="v"></Item>
  </div>
</template>

<script>
import Item from "./Item";
export default {
  name: "",
  components: { Item },
  data() {
    return {};
  },
  props: ["items"],
};
</script>

<style></style>

Item.vue

<template>
  <ul>
    <li>
      <div>{{ item.name }}</div>
      <Item v-for="(v, i) in item.child" :key="i" :item="v"></Item>
    </li>
  </ul>
</template>

<script>
export default {
  name: "Item",
  components: {},
  data() {
    return {};
  },
  props: ["item"],
};
</script>

<style></style>

JS递归方法实现:

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
</head>

<body>
    <button onclick="fun()">递归测试</button>
    <div id="div">

    </div>

    <script>
        //模拟数据
        var data = [{
            name: 1,
            sub: [{
                name: '1-1',
                sub: []
            }]
        }, {
            name: 2,
            sub: [{
                    name: "2-1",
                    sub: [{
                            name: '2-1-1',
                            sub: []
                        }, {
                            name: '2-1-2',
                            sub: []
                        }

                    ]
                }, {
                    name: "2-2",
                    sub: [{
                        name: '2-2-1',
                        sub: []
                    }, {
                        name: '2-2-2',
                        sub: [{
                            name: '2-2-2-1',
                            sub: []
                        }]
                    }]
                }

            ]
        }, {
            name: 3,
            sub: []
        }]


        var div = document.getElementById('div')
        var str = '';

      //递归函数
function list(data) { if (data) { if (data.length > 0) { str += "<ul>"; for (let v = 0; v < data.length; v++) { const item = data[v]; str += '<li>' + item.name; list(item.sub) str += '</li>'; } str += "</ul>"; } } } list(data) console.log(str) div.innerHTML = str;


//以下是递归测试函数,与树形菜单无关
var arr = []; function fun() { var num = parseFloat(prompt("输入数字:")); if (typeof(num) == 'number') { while (num > 0) { arr.push(num) num--; } //console.log(arr) } } var arrlist = []; // var data=[1,[2,3],[4,[5,6,[8]]],9,[10]]; var fun3 = arr => [...arr].map((item) => Array.isArray(item) ? fun3(item) : arrlist.push(item)); fun3(data) // console.log( fun3(data)) </script> </body> </html>

使用VUE + element-ui   实现树形菜单:

<template>
  <div class="custom-tree-container">
    <div class="block">
      <p>使用 render-content</p>
      <el-tree
        :data="data"
        show-checkbox
        node-key="id"
        default-expand-all
        :expand-on-click-node="false"
        :render-content="renderContent"
      ></el-tree>
    </div>
    <div class="block">
      <p>使用 scoped slot</p>
      <el-tree
        :data="data"
        show-checkbox
        node-key="id"
        default-expand-all
        :expand-on-click-node="false"
      >
        <span class="custom-tree-node" slot-scope="{ node, data }">
          <span>{{ node.label }}</span>
          <span>
            <el-button type="text" size="mini" @click="() => append(data)">Append</el-button>
            <el-button type="text" size="mini" @click="() => remove(node, data)">Delete</el-button>
          </span>
        </span>
      </el-tree>
    </div>

    <button @click="getAdd">+</button>
    <button @click="getjian">-</button>
  </div>
</template>
<script>
let id = 1000;

export default {
  data() {
    const data = [
      {
        name: "北京",
        sub: [
          {
            name: "北京",
            sub: [
              { name: "东城区" },
              { name: "西城区" },
              { name: "南城区" },
              { name: "北城区" }
            ]
          }
        ]
      },
      {
        name: "广东",
        sub: [
          {
            name: "广州",
            sub: [{ name: "越秀区" }, { name: "白云区" }, { name: "海珠区" }]
          },
          {
            name: "深圳",
            sub: [{ name: "蛇口区" }, { name: "保安区" }, { name: "盐田区" }]
          }
        ]
      },
      {
        name: "湖北",
        sub: [
          {
            name: "武汉",
            sub: [{ name: "江夏区" }, { name: "洪山区" }, { name: "江汉区" }]
          },
          {
            name: "天门市",
            sub: [{ name: "精灵" }, { name: "小班" }, { name: "打扮" }]
          }
        ]
      }
    ];
   //关键部分
    let _data = function(data) {
      return data.map(v => {
        if (v.sub) {        // 遍历数据,将菜单数据赋值给 ui框架指定属性名
          v.label = v.name;
          v.children = v.sub;
          return _data(v.sub);
        }
        if (v.name && !v.sub) {
          v.label = v.name;
          return 123;
        }
      });
    };
    _data(data);
    return {
      data: JSON.parse(JSON.stringify(data)),  //将处理过的数据进行深刻隆
      data: JSON.parse(JSON.stringify(data))
    };
  },

  methods: {
    append(data) {
      const newChild = { id: id++, label: "testtest", children: [] };
      if (!data.children) {
        this.$set(data, "children", []);
      }
      data.children.push(newChild);
    },

    remove(node, data) {
      const parent = node.parent;
      const children = parent.data.children || parent.data;
      const index = children.findIndex(d => d.id === data.id);
      children.splice(index, 1);
    },

    renderContent(h, { node, data, store }) {
      return (
        <span class="custom-tree-node">
          <span>{node.label}</span>
          <span>
            <el-button
              size="mini"
              type="text"
              on-click={() => this.append(data)}
            >
              Append
            </el-button>
            <el-button
              size="mini"
              type="text"
              on-click={() => this.remove(node, data)}
            >
              Delete
            </el-button>
          </span>
        </span>
      );
    },
    getAdd() {
      this.$store.commit("increment");
      console.log("我是加法" + this.$store.state.count);
    },
    getjian() {
      this.$store.commit("jian", 2);
      console.log("我是加Z法" + this.$store.state.count);
    }
  },
  mounted() {
    console.log(this.$store.state.count);
  }
};
</script>

<style>
.custom-tree-node {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 14px;
  padding-right: 8px;
}
</style>

 js  实现无极限目录树完整版

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        div {
            margin-left: 20px;
            cursor: pointer;
        }
        .has-child {
            position: relative;
        }
        .has-child::before {
            content: '+';
            position: absolute;
            left: -20px;
        }
        .has-child > div {
            display: none;
        }
        .has-child.expend > div {
            display: block;
        }
        .has-child.expend::before {
            content: '-';
        }
    </style>
</head>
<body>
    <div id="demo"></div>
    <script>
        var data = [{
            name: '一级标题1',
            children: [{
                name: '二级标题1',
                children: [{
                    name: '三级标题'
                }]
            }, {
                name: '二级标题2',
                children: [{
                    name: '三级标题'
                }]
            }]
        }, {
            name: '一级标题2',
            children: [{
                name: '二级标题1',
                children: [{
                    name: '三级标题',
                    children: {
                        name: '四级标题'
                    }
                }]
            }]
        }, {
            name: '一级标题3',
            children: [{
                name: '二级标题1',
                children: [{
                    name: '三级标题'
                }]
            }, {
                name: '二级标题2',
                children: [{
                    name: '三级标题'
                }]
            }, {
                name: '二级标题3'
            }]
        }]
        
        // 用来创建目录树结构的函数
        /**
        * data 目录树的数据
        * parentNode:   将目录树结构插入到哪个节点下
        */
        function dTree(data, parentNode) {
            // 做一个兼容  如果当前没有传递父节点则创建一个父节点
            if (!parentNode) {
                parentNode = document.createElement('div');
                parentNode.className = 'root';
            }
            // 遍历数据中的每一项创建目录树的结构
            data.forEach(function (item) {
                var node = document.createElement('div');
                node.innerText = item.name;
                // 阻止事件冒泡
                node.onclick = function (e) {
                    e.stopPropagation();
                }
                // 判断当前标题下面是否含有子标题如果含有的话继续创建标题结构
                if(item.children && item.children.length > 0) {
                    // 如果含有子标题则添加一个has-child的类名
                    node.className = 'has-child';
                    // 如果含有子标题则当前的标题可以点击展开
                    node.onclick = function (e) {
                        e.stopPropagation();
                        if (this.classList.contains('expend')) {
                            this.classList.remove('expend')
                        } else {
                            this.classList.add('expend')
                        }
                        
                    }
                    // 如果有子标题的话 需要继续创建子标题的结构
                    dTree(item.children, node);
                }
                parentNode.appendChild(node);
            })
            // 当前函数直接返回创建出来的目录树结构  由于所有的结构都插入到了父节点当中,因此可以返回父节点
            return parentNode
        }

        var demo = document.getElementById('demo');

        dTree(data, demo);

    </script>
</body>
</html>

...

原文地址:https://www.cnblogs.com/wxyblog/p/11618686.html