出现该情况的原因是vue-router安装的版本太高，一般vue2的项目对应的版本是vue-router@3版本
①在控制台输入： cnpm install --save vue-router@3.5.3 重新安装vue-router即可解决
- properties TypeError undefined Uncaught installproperties typeerror undefined uncaught typeerror undefined uncaught property addeventlistener typeerror uncaught property properties typeerror undefined reading typeerror undefined property cannot typeerror non-mysql undefined property typeerror undefined property upgrade typeerror undefined property webpack quot properties typeerror undefined emitsoptions properties typeerror uncaught