react中运行报错。Check the render method of `CountLineData`.

 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