LayUI tree组件实现展开全部和折叠全部的功能

<div id="menuTree" class="demo-tree-more"></div>

   tree.render({
       elem: '#menuTree',
       data: getData(),  //ajax获取data数据
       showCheckbox: true,  //是否显示复选
       id: 'demoId' 
   });

//menuTree换成你自己的id就行
var treeContainer = document.querySelector('#menuTree');
var expandIcons = treeContainer.querySelectorAll('.layui-icon-addition');  //展开代码
var expandIcons = treeContainer.querySelectorAll('.layui-icon-subtraction'); //折叠代码
expandIcons.forEach(function(icon) {
    var clickEvent = new MouseEvent('click', {
    'view': window,
    'bubbles': true,
    'cancelable': true
});
icon.dispatchEvent(clickEvent);
});