js-waku-examples/examples/light-chat/index.js

import {
  createLightNode,
  bytesToUtf8,
  utf8ToBytes,
  waitForRemotePeer,
  createDecoder,
  createEncoder,
} from "https://unpkg.com/@waku/sdk@0.0.18/bundle/index.js";

const CONTENT_TOPIC = "/toy-chat/2/huilong/proto";

const ui = initUI();
runApp(ui).catch((err) => {
  console.error(err);
  ui.setStatus(`error: ${err.message}`, "error");
});

async function runApp(ui) {
  ui.setStatus("connecting...", "progress");

  const { info, sendMessage, unsubscribeFromMessages } = await initWakuContext({
    contentTopic: CONTENT_TOPIC,
    onMessageReceived: ui.renderMessage,
  });

  ui.setStatus("connected", "success");

  ui.setLocalPeer(info.localPeerId);
  ui.setRemotePeer(info.remotePeerIds);
  ui.setContentTopic(info.contentTopic);

  ui.onSendMessage(sendMessage);

  ui.onExit(async () => {
    ui.setStatus("disconnecting...", "progress");
    await unsubscribeFromMessages();
    ui.setStatus("disconnected", "terminated");
    ui.resetMessages();
  });
}

async function initWakuContext({ contentTopic, onMessageReceived }) {
  const Decoder = createDecoder(contentTopic);
  const Encoder = createEncoder({ contentTopic });

  const ChatMessage = new protobuf.Type("ChatMessage")
    .add(new protobuf.Field("timestamp", 1, "uint64"))
    .add(new protobuf.Field("nick", 2, "string"))
    .add(new protobuf.Field("text", 3, "bytes"));

  const node = await createLightNode({ defaultBootstrap: true });

  await node.start();
  await waitForRemotePeer(node);

  // Set a filter by using Decoder for a given ContentTopic
  const unsubscribeFromMessages = await node.filter.subscribe(
    [Decoder],
    (wakuMessage) => {
      const messageObj = ChatMessage.decode(wakuMessage.payload);
      onMessageReceived({
        ...messageObj,
        text: bytesToUtf8(messageObj.text),
      });
    }
  );

  const localPeerId = node.libp2p.peerId.toString();

  const remotePeers = await node.libp2p.peerStore.all();
  const remotePeerIds = remotePeers.map((peer) => peer.id.toString());

  return {
    unsubscribeFromMessages,
    info: {
      contentTopic,
      localPeerId,
      remotePeerIds,
    },
    sendMessage: async ({ text, nick }) => {
      if (!text || !nick) {
        return;
      }

      const protoMessage = ChatMessage.create({
        nick,
        timestamp: Date.now(),
        text: utf8ToBytes(text),
      });

      await node.lightPush.send(Encoder, {
        payload: ChatMessage.encode(protoMessage).finish(),
      });
    },
  };
}

// UI adapter
function initUI() {
  const exitButton = document.getElementById("exit");
  const sendButton = document.getElementById("send");

  const statusBlock = document.getElementById("status");
  const localPeerBlock = document.getElementById("localPeerId");
  const remotePeerId = document.getElementById("remotePeerId");
  const contentTopicBlock = document.getElementById("contentTopic");

  const messagesBlock = document.getElementById("messages");

  const nickText = document.getElementById("nickText");
  const messageText = document.getElementById("messageText");

  return {
    // UI events
    onExit: (cb) => {
      exitButton.addEventListener("click", cb);
    },
    onSendMessage: (cb) => {
      sendButton.addEventListener("click", async () => {
        await cb({
          nick: nickText.value,
          text: messageText.value,
        });
        messageText.value = "";
      });
    },
    // UI renderers
    setStatus: (value, className) => {
      statusBlock.innerHTML = `<span class=${className || ""}>${value}</span>`;
    },
    setLocalPeer: (id) => {
      localPeerBlock.innerText = id.toString();
    },
    setRemotePeer: (ids) => {
      remotePeerId.innerText = ids.join("\n");
    },
    setContentTopic: (topic) => {
      contentTopicBlock.innerText = topic.toString();
    },
    renderMessage: (messageObj) => {
      const { nick, text, timestamp } = messageObj;
      const date = new Date(timestamp);

      // WARNING: XSS vulnerable
      messagesBlock.innerHTML += `
                <div class="message">
                    <p>${nick} <span>(${date.toDateString()})</span>:</p>
                    <p>${text}</p>
                <div>
            `;
    },
    resetMessages: () => {
      messagesBlock.innerHTML = "";
    },
  };
}