POC: PureScript in Signal Desktop

[gasi]

Highlights

• Define types such as Message, Conversation, based on researching and reconstructing the shape and types of existing and legacy data in IndexedDB as well as how the current app consumes data, etc.
• Build raw IndexedDB access layer using purescript-indexeddb.
• Parse existing IndexedDB data into strong types.
• Attachment type module passes existing unit tests.
• Render conversation view using PureScript Halogen library (similar to React) integrated with existing code.
• Showcase simple FFI for:
  • libphonenumber
  • Conversation.compareTitle
  • Avatar.hashCode
• Showcase the power of case expressions and compile-time checking that all cases have been handled:
  • toContactDetails:

    Signal-Desktop/purescript/src/Signal/Components/ConversationList.purs

    Lines 154 to 165 in 4ed4898

    	toContactDetails :: Conversation -> ContactDetails
    	toContactDetails (Group o) =
    	{ name : o.name
    	, lastMessage : o.lastMessage
    	}
    	toContactDetails (Private o) =
    	{ name : o.name <|> o.profileName <|> formatPhoneNumber o.id
    	, lastMessage : o.lastMessage
    	}
    	where
    	formatPhoneNumber :: String -> Maybe String
    	formatPhoneNumber = PN.formatString PN.National

  • renderAvatar:

    Signal-Desktop/purescript/src/Signal/Components/ConversationList.purs

    Lines 178 to 180 in 4ed4898

    	style (Image u) = backgroundImage $ url $ u
    	style GroupIcon = backgroundImage $ url $ "images/group_default.png"
    	style _ = pure unit