It's return error when i try this code
react-intl version 3.1.6 && react version 16.9
import { IntlProvider, FormattedMessage , addLocaleData} from 'react-intl';
I'm still investigating but it looks like addLocaleData was removed as a breaking change for v3.
https://formatjs.io/docs/react-intl/upgrade-guide-3x
This was a bit confusing for me too because a lot of the tutorials and guides out there still use addLocaleData.