Warning: React.createElement: type is invalid -- expected a string (for built-in components) or a class/function (for composite components) but got: undefined. You likely forgot to export your component from the file it's defined in. Check the render method of `CountLineData`.
本错误的原因:在页面上引用多加了{},唉,害死人呀
所以说,这种错误解决的办法只有细心,没别的