input's event.target is null within this.setState [React.js]

Question

In my react component I have a file input:

` 

and my onFileChan

Answer 1

The setState function is executed in asynchronous context.

By the time the state is updated the e.target reference might or might not be gone.

const file = e.target.files[0]; can be used to "remember" the value as in your example.