Reaction

Emojis are widely used in real-time chats because they allow users to express their feelings in a direct and vivid way. In Agora Chat, "reactions" allow users to quickly react to a message using emojis in one-to-one chats and chat groups. In group chats, reactions can also be used to cast a vote, for example, by calculating the number of different emojis attached to the message.

The following illustrations show the implementation of adding a reaction to a message, and what retrieving a list of reactions (with related information) looks like.

• Adding a reaction

  

• Retrieving a list of reactions

  

This page shows how to use the Agora Chat SDK to implement reactions in your project.

Understand the tech

The SDK provides the following APIs to implement reaction functionalities:

• addReaction: Adds a reaction to the specified message.
• deleteReaction: Removes the reaction from the specified message.
• getReactionList: Retrieves a list of reactions from the server.
• getReactionDetail: Retrieves the details of the reaction from the server.

Prerequisites

Before proceeding, ensure that your environment meets the following requirements:

• The project integrates a version of the Agora Chat SDK later than v1.0.3 and has implemented the basic real-time chat functionalities.
• You understand the API call frequency limit as described in Limitations.

Implementation

This section introduces how to implement reaction functionalities in your project.

Add a reaction

Call addReaction to add a reaction to the specified message. You can use onReactionChange to listen for the state of adding the reaction.

// Add a reaction
conn.addReaction({ messageId: "messageId", reaction: "reaction" });
// Listen for the state of the reaction.
conn.addEventHandler("REACTION", {
  onReactionChange: (reactionMsg) => {
    console.log(reactionMsg);
  },
});

Remove a reaction

Call deleteReaction to remove the specified reaction. You can also listen for the reaction change in onReactionChange.

// Remove the reaction.
conn.deleteReaction({ messageId: "messageId", reaction: "reaction" });
// Listen for reaction state change.
conn.addEventHandler("REACTION", {
  onReactionChange: (reactionMsg) => {
    console.log(reactionMsg);
  },
});

Retrieve a list of reactions

Call getReactionList to retrieve a list of reactions from the server. This method also returns the basic information of the reactions, including the content of the reaction, the number of users that added or removed the reaction, and a list of the first three user IDs that added or removed the reaction.

conn
  .getReactionList({ chatType: "singleChat", messageId: "messageId" })
  .then((res) => {
    console.log(res);
  });

Retrieve the details of the reaction

Call getReactionDetail to get the detailed information of the reaction from the server. The detailed information includes the reaction content, the number of users that added or removed the reaction, and the complete list of user IDs that added or removed the reaction.

conn
  .getReactionDetail({
    messageId: "messageId",
    reaction: "reaction",
    cursor: null,
    pageSize: 20,
  })
  .then((res) => {
    console.log(res);
  });

Retrieve the reaction in the roaming message

When calling fetchHistoryMessages to retrieve historical messages from the server, if the message has a reaction attached to it, the retrieved message body also contains the information of the reaction.

conn.fetchHistoryMessages({ queue: "user", count: 20 }).then((messages) => {
  console.log(messages);
});

Next steps

Reactions are also supported in the Chat UIKit, which contains a wider range of emojis. You can also use the UIKit to implement reactions in your project.