code: function filterTree (obj, iterate, options, context) {
    var result = []
    if (obj && iterate) {
      context = context || this
      eachTree(obj, function (item, index, items, path, parent) {
        if (iterate.call(context, item, index, items, path, parent)) {
          result.push(item)
        }
      }, options)
    }
    return result
  }
docs: 从树结构中根据回调过滤数据
  
  @param {Object} obj 对象/数组
  @param {Function} iterate(item, index, items, path, parent) 回调
  @param {Object} options {children: 'children'}
  @param {Object} context 上下文
  @return {Array}