App.js

//frontend/src/App.js:14
const register = async (e) => {
    try {
      e.preventDefault();

      const response = await fetch('http://localhost:8080/customer-login', {
        method: 'POST',
        headers: {
          'Accept': 'application/json',
          'Content-Type': 'application/json',
        },
        body: JSON.stringify({
          firstName,
          lastName,
          email,
        }),
      });

      const { customerId, customerToken, channelId, streamApiKey } = await response.json();
      const chatClient = new StreamChat(streamApiKey);

      await chatClient.setUser(
        {
          id: customerId,
          name: firstName,
        },
        customerToken,
      );

      const channel = chatClient.channel('messaging', channelId);

      setChatClient(chatClient);
      setChannel(channel);

    } catch (e) {
      console.error(e);
    }
  };