> ## Documentation Index
> Fetch the complete documentation index at: https://cometchat-013b37f0.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.
# Reactions
Enhance user engagement in your chat application with message reactions. Users can express their emotions using reactions to messages. This feature allows users to add or remove reactions, and to fetch all reactions on a message. You can also listen to reaction events in real-time. Let's see how to work with reactions in CometChat's iOS SDK.
## Add a Reaction
Users can add a reaction to a message by calling `addReaction` with the message ID and the reaction emoji.
```swift theme={null}
CometChat.addReaction(messageId: 148, reaction: "😴") { message in
print("message reaction added successfully \(message.getReactions())")
} onError: { error in
print("some error occured when adding reaction \(error?.errorDescription)")
}
```
You can react on Text, Media and Custom messages.
## Remove a Reaction
Removing a reaction from a message can be done using the `removeReaction` method.
```swift theme={null}
CometChat.removeReaction(messageId: 148, reaction: "😴") { message in
print("message reaction removed successfully \(message.getReactions())")
} onError: { error in
print("some error occured when removing reaction \(error?.errorDescription)")
}
```
## Fetch Reactions for a Message
To get all reactions for a specific message, first create a `ReactionsRequest` using `ReactionsRequestBuilder`. You can specify the number of reactions to fetch with `setLimit` with max limit 100. For this, you will require the ID of the message. This ID needs to be passed to the `setMessageId()` method of the builder class. The `set(reaction: String)` will allow you to fetch details for specific reaction or emoji.
| Methods | Description |
| ------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `setMessageId(messageId: Int)` | Specifies the unique identifier of the message for which you want to fetch reactions. This parameter is mandatory as it tells the SDK which message's reactions are being requested. |
| `setReaction(reaction: String)` | Filters the reactions fetched by the specified reaction type (e.g., "😊", "😂", "👍"). When set, this method will cause the `ReactionsRequest` to only retrieve details of the provided reaction for the given message. |
### Fetch Next Reactions
The `fetchNext()` method fetches the next set of reactions for the message.
```swift theme={null}
var reactionsRequest = ReactionsRequestBuilder().setLimit(limit: 30).setMessageId(messageId: 148).build()
reactionsRequest.fetchNext { reactions in
for reaction in reactions{
print("reaction is \(reaction.stringValue())")
}
} onError: { error in
print("error caught in fetching next reactions is \(error?.errorDescription)")
}
```
### Fetch Previous Reactions
The `fetchPrevious()` method fetches the previous set of reactions for the message.
```swift theme={null}
var reactionsRequest = ReactionsRequestBuilder().setLimit(limit: 30).setMessageId(messageId: 148).build()
reactionsRequest.fetchPrevious { reactions in
for reaction in reactions{
print("reaction is \(reaction.stringValue())")
}
} onError: { error in
print("error caught in fetching previous reactions is \(error?.errorDescription)")
}
```
## Real-time Reaction Events
Keep the chat interactive with real-time updates for reactions. Register a listener for these events and make your UI responsive.
```swift theme={null}
let listenerID = "UNIQUE_LISTENER_ID"
CometChat.addMessageListener(listenerID, self)
extension YourAppViewController: CometChatMessageDelegate {
func onMessageReactionAdded(reactionEvent: ReactionEvent) {
print("Reaction Added : \(reactionEvent) ")
}
func onMessageReactionRemoved(reactionEvent: ReactionEvent) {
print("Reaction Removed : \(reactionEvent) ")
}
}
```
## Removing a Reaction Listener
To stop listening for reaction events, remove the listener as follows:
```swift theme={null}
let listenerID = "UNIQUE_LISTENER_ID"
CometChat.removeMessageListener("reactionListener");
```
## Get Reactions List
To retrieve the list of reactions reacted on particular message, you can use the `message.reactions` method. This method will return an array containing the reactions, or an empty array if no one reacted on the message.
```swift theme={null}
message.reactions
```
## Check if Logged-in User has Reacted on Message
To check if the logged-in user has reacted on a particular message or not, You can use the `reactedByMe()` method on any `ReactionCount` object instance. This method will return a boolean value, `true` if the logged-in user has reacted on that message, otherwise `false`.
```swift theme={null}
for reactionCount in message.reactions {
print("isReactedByMe \(reactionCount.reactedByMe)") //Return true is logged-in user reacted on that message, otherwise false
}
```
## Updated Message With Reaction Info
When a user adds or removes a reaction, you will receive a real-time event. Once you receive the real time event you would want to update the message with the latest reaction information. To do so you can use the `updateMessageWithReactionInfo()` method.
The `updateMessageWithReactionInfo()` method provides a seamless way to update the reactions on a message instance (`BaseMessage`) in real-time. This method ensures that when a reaction is added or removed from a message, the `BaseMessage` object's `reactions` property reflects this change immediately.
When you receive a real-time reaction event (`ReactionEvent`), call the `updateMessageWithReactionInfo()` method, passing the BaseMessage instance (`message`), reaction data from the reaction event (`ReactionEvent.reaction`) and reaction event action type (`ReactionAction.REACTION_ADDED` or `ReactionAction.REACTION_REMOVED`) that corresponds to the message being reacted to.
```swift theme={null}
// The message to which the reaction is related
var message : BaseMessage = ...
// The reaction event data received in real-time
var messageReaction : MessageReaction = ...
// The recieved reaction event real-time action type. Can be ReactionAction.REACTION_ADDED or ReactionAction.REACTION_REMOVED
var action = ReactionAction.REACTION_ADDED
var modifiedBaseMessage : BaseMessage = CometChat.updateMessageWithReactionInfo(
baseMessage : baseMessage,
messageReaction : messageReaction,
action : action
)
```
After calling this method, the `message` instance's reactions are updated. You can then use `message.reactions` to get the latest reactions and refresh your UI accordingly.