React错误收集

1.??Uncaught Error: Element 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,or you might have mixed up default and named imports

这个错误，最常见的问题是import组件出错。例如，

import { com } from ‘t-com‘  
//写成了  
import com from ‘t-com‘

或者

import com from ‘t-com‘  
//写成了  
import { com } from ‘t-com‘