Document Picker for React Native using Document Providers. If the user cancels the document picker without choosing a file (by pressing the system back button on Android or the Cancel button on iOS), the Promise will be rejected with a cancellation error. You can check for this error using DocumentPicker.isCancel(err) allowing you to ignore it and cleanup any parts of your interface that may not be needed anymore. If the user somehow manages to open multiple file pickers (e.g. due the app being...