It is now possible to leverage Contentful's native dialogs when working with UI Extensions. We added support for confirm, alert and prompt to the SDK from version 3.4.2. To learn about the new functionality please refer to the reference documentation.

We additionally added:

• locale names: extension.locales.names -> { pl: 'Polski', 'en-US': 'English (US)' }
• field type and validations for all entry fields: extension.entry.fields[id].type and extension.entry.fields[id].validations