侧边栏菜单的JS初始化

有小伙伴提到想用js初始化左侧菜单，这里简单写了个方法。

这里以iframe版本为例。您可以将下面的代码放到 `index.min.js` 中，要放到 `;jQuery( function() {});` 外面，然后直接使用 `setSidebar(menus);`，调用时传入的参数，可以是 `json` 字符串，也可以是对象，不需要是树状结构的。

以下是主要的js代码。

> 注意：因IE浏览器不支持ES6的语法，请考虑自身的应用情况是否使用treeData方法（树状结构数据可由后端先处理完成，前端加载菜单时放在index.min.js之前）。

```javascript
/**
 * 菜单
 * @param data 菜单JSON数据
 *        id 菜单唯一ID
 *        name 菜单名称
 *        url 菜单链接地址
 *        icon 图标
 *        pid  父级ID
 *        is_out 是否外链0否|1是,外链a标签没有class='multitabs'
 *        is_home 是否首页
 */
var setSidebar = function(data){
    if (data.length == 0) return false;
    var treeObj = treeData(data, 'id', 'pid', 'children');
    html = createMenu(treeObj, true);
    $('.sidebar-main').append(html);
}

/**
 * @author CSDN 蔚莱先森
 * @param source json数据源
 * @param id 主键ID
 * @param parendId 父级ID名称
 * @param children 子级名称
 */
var treeData = function (source, id, parentId, children){
    let cloneData = (typeof source == 'object') ? source : JSON.parse(source);
    return cloneData.filter(father=>{
        let branchArr = cloneData.filter(child => father[id] == child[parentId]);
        branchArr.length>0 ? father[children] = branchArr : ''
        return father[parentId] == 0
    })
}
```

如果你是v4的模板，请将上面的代码做一点点更改：
```javascript
// v3的
var menu_body = is_frist ? '<ul class="nav nav-drawer">' : '<ul class="nav nav-subnav">';

// v4的
var menu_body = is_frist ? '<ul class="nav-drawer">' : '<ul class="nav nav-subnav">';
```

菜单这一块的html代码，保留如下：
```html

<div class="lyear-layout-sidebar-scroll">
  <nav class="sidebar-main"></nav>
</div>

<div class="lyear-layout-sidebar-info lyear-scroll"> 
  <nav class="sidebar-main"></nav>
</div>
```
也可以将代码封装到lightyear.js中，在index.html中引入，然后像这样调用 lightyear.sidebar(menus);。
```javascript
return {
    // 省略...
	
    // 左侧菜单
    sidebar : function(data) {
        setSidebar(data);
    }
};
```
记得最后return里面要加上上面的代码。最后附上一段菜单的json串。
```json
[{"id":"1","name":"后台首页","url":"lyear-main.html","pid":0,"icon":"mdi mdi-home","is_out":0,"is_home":1},{"id":"2","name":"UI 元素","url":"#","pid":0,"icon":"mdi mdi-palette","is_out":0,"is_home":0},{"id":"3","name":"按钮","url":"lyear_ui_buttons.html","pid":2,"icon":"","is_out":0,"is_home":0},{"id":"4","name":"卡片","url":"lyear_ui_cards.html","pid":2,"icon":"","is_out":0,"is_home":0},{"id":"5","name":"格栅","url":"lyear_ui_grid.html","pid":2,"icon":"","is_out":0,"is_home":0},{"id":"6","name":"多级菜单","url":"#","pid":0,"icon":"mdi mdi-menu","is_out":0,"is_home":0},{"id":"7","name":"一级菜单","url":"#!","pid":6,"icon":"","is_out":0,"is_home":0},{"id":"8","name":"一级菜单","url":"#!","pid":6,"icon":"","is_out":0,"is_home":0},{"id":"9","name":"二级菜单","url":"#!","pid":8,"icon":"","is_out":0,"is_home":0},{"id":"10","name":"二级菜单","url":"#!","pid":8,"icon":"","is_out":0},{"id":"11","name":"三级菜单","url":"#!","pid":10,"icon":"","is_out":0,"is_home":0},{"id":"12","name":"三级菜单","url":"#!","pid":10,"icon":"","is_out":0,"is_home":0}]
```
由于上面生成树状结构的方法不支持IE，附上另一个tree结构数据生成的方法：
```javascript
/**
 * 树状的算法
 * @params list     代转化数组
 * @params parentId 起始节点
 * @params idName 主键ID名
 * @params parentIdName 父级ID名称
 * @params childrenName 子级名称
 * @author CSDN博主「伤包子」
 */
function getTrees(list, parentId, idName, parentIdName, childrenName) {
    let items= {};
    // 获取每个节点的直属子节点，*记住是直属，不是所有子节点
    for (let i = 0; i < list.length; i++) {
         let key = list[i][parentIdName];
         if (items[key]) {
             items[key].push(list[i]);
         } else {
             items[key] = [];
             items[key].push(list[i]);
         }
     }
     return formatTree(items, parentId, idName, childrenName);
}

/**
 * 利用递归格式化每个节点
 */
function formatTree(items, parentId, idName, childrenName) {
    let result = [];
    if (!items[parentId]) {
        return result;
    }
    for (let t in items[parentId]) {
        items[parentId][t][childrenName] = formatTree(items, items[parentId][t][idName], idName, childrenName)
        result.push(items[parentId][t]);
    }
    return result;
}
```
[点击查看演示示例](http://example.itshubao.com/example/114.html "点击查看演示示例")