Add a way to go ChatId -> UserId

crates/teloxide-core/CHANGELOG.md

@@ -16,9 +16,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - `Seconds` type, which represents a duration is seconds ([#859][pr859])
 - `VideoChatEnded::duration` field that was previously missed ([#859][pr859])
 - `ThreadId` newtype over `MessageId`, used for identifying reply threads ([#887][pr887])
+- `ChatId::as_user` ([#905][pr905])
 
 [pr851]: https://github.com/teloxide/teloxide/pull/851
 [pr887]: https://github.com/teloxide/teloxide/pull/887
+[pr905]: https://github.com/teloxide/teloxide/pull/905
 
 ### Fixed
 

crates/teloxide-core/src/types/chat_id.rs

@@ -50,6 +50,15 @@ impl ChatId {
         matches!(self.to_bare(), BareChatId::Channel(_))
     }
 
+    /// Returns user id, if this is an id of a user.
+    #[must_use]
+    pub fn as_user(self) -> Option<UserId> {
+        match self.to_bare() {
+            BareChatId::User(u) => Some(u),
+            BareChatId::Group(_) | BareChatId::Channel(_) => None,
+        }
+    }
+
     /// Converts this id to "bare" MTProto peer id.
     ///
     /// See [`BareChatId`] for more.