deployment-talks/chat-app/frontend/index.js

import m from "mithril";
import { createWebSocket } from "./websocket";

// on new message event, call m.redraw();
const messages = [];
const socket = createWebSocket();

socket.onmessage = function (event) {
  if (event.type === "message") {
    const message = JSON.parse(event.data);
    messages.push(message);
    m.redraw();
  }
}

function newMessageText(name, message) {
  return [
    m("span.chatter", name + ": "),
    m("span.chatter-message", message)
  ];
}

const MessageBox = {
  view: function () {
    return m(".messages", messages.map(function(message) {
      return m(".message", newMessageText(message.chatter, message.message));
    }));
  }
};

function clearMessageBox() {
  const messageBox = document.getElementById("message");
  messageBox.value = "";
}

function sendMessage(e) {
  e.preventDefault();

  const form = new FormData(e.target);
  const message = {};

  for (const [key, value] of form.entries()) {
    message[key] = value;
  }

  socket.send(JSON.stringify(message));
  clearMessageBox();
}

const MessageInput = {
  view: function () {
    return m("div.chat-input", [
      m("form", { method: "post", onsubmit: sendMessage }, [
        m("input", { name: "chatter", placeholder: "Name" }),
        m("input", { name: "message", placeholder: "Message", id: "message", required: true }),
        m("input", { type: "submit", value: "Send" })
      ])
    ]);
  }
};

const Chat = {
  view: function(vnode) {
    return m("div", [
      m(MessageBox),
      m(MessageInput)
    ])
  }
};

m.mount(document.getElementById("app"), Chat);