App.js

initialiseChatClient = async () => {
  const response = await fetch("http://localhost:8080/v1/token", {
    method: "POST",
    mode: "cors",
    headers: {
      "Content-Type": "application/json"
    },
    body: JSON.stringify({
      id: this.user.id,
      name: this.user.name
    })
  });
  const streamServerInfo = await response.json();

  this.chatClient = new StreamChat(streamServerInfo.apiKey);
  this.chatClient.setUser(this.user, streamServerInfo.token);

  this.conversation = this.chatClient.channel("commerce", "conversational-ui");

  await this.conversation.watch();
  this.conversation.on("message.new", this.onNewMessage;
};