A sample sketch of an idea in code

gistfile1.txt

/*

Can't say this here, business doesn't know Node

class BlockFactory {
    fun nodeFor(block:TextBlock):Node {
        Make the correct node given that it's a text block and return it.
    }

    fun nodeFor(block:TodoBlock):Node {
    }

    fun nodeFor(block:UsersPageBlock): Node {
    }
}
*/

enum class BlockType {
    text,
    rich,
    todo,
    users,
}

interface PageBlock {
    val type: BlockType
}

@Serializable
data class TextBlock(val text: String) : PageBlock {
    override val type: BlockType = BlockType.text
}

@Serializable
data class TodoBlock(val isChecked: Boolean) : PageBlock {
    override val type: BlockType = BlockType.todo
}

@Serializable
data class UserEntry(val name: String, val email: String, val somethingElse: String)

@Serializable
data class UsersPageBlock(val page: Int, val users: List<UserEntry>) : PageBlock {
    override val type: BlockType = BlockType.users
}