(React-Native) undefined is not a constructor evaluating 'new FormData()'

I got into this problem as well and that's because I have imported them on top. If you have done like what I did:

import { FormData } from 'react';

or

import { FormData } from 'react-native';

Just remove "FormData" from your imports and it will work like magic. FormData doesn't have to be imported for it to be working.