2.js

const startChat = async () => {
  const response = await axios.post("http://localhost:8080/stream-chat-credentials", {
    username, leadId
  });
  const token = response.data.token;
  const channelId = response.data.channelId;
  const chatClient = new StreamChat(response.data.apiKey);

  await chatClient.setUser({ id: response.data.userId, name: response.data.userName }, token);
  const channel = chatClient.channel("messaging", channelId);

  setChatClient(chatClient);
  setChannel(channel);
}