Cannot read property 'length' of undefined TypeError: Cannot read property 'length' of undefined at L._updatePosition (<anonymous>:2:941402) at <anonymous>:2:604126
Cannot read property \'length\' of undefined
TypeError: Cannot read property \'length\' of undefined
at L._updatePosition (<anonymous>:2:941402)
at <anonymous>:2:604126
你好，哪个小程序，麻烦提供出现问题的具体机型、微信版本号、系统版本号，以及能复现问题的代码片段（https://developers.weixin.qq.com/miniprogram/dev/devtools/minicode.html）
Cannot read property \'length\' of undefined TypeError: Cannot read property \'length\' of undefined at L._updatePosition (<anonymous>:2:941402) at <anonymous>:2:604126Win7/Win10客户端3.0.0，基础库版本2.12.1
是基础库错误信息