An IRC WebSocket client that reads Twitch channel chat without the need to authenticate

twitchchatreader.js

/**
 * MIT License
 *
 * Copyright (c) 2022 Giuseppe Eletto <[email protected]>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */
var TwitchChatReader = (function () {
  // Constants
  var IRC_WEBSOCKET = "wss://irc-ws.chat.twitch.tv";
  var MSG_REGEX = /^(?:@(\S+)\ +)?(?::(?:(?:(\w+)!(\S+))|(\S+))\ +)?(?:(\w+)\ *)(?:(\w+)[ =]*)?(?:\#(\w+)\ *)?(?::(.+))?$/m;
  var TAG_REGEX = /([\w\+][^\=]+)\=(?:(\d+)|([^\;\s]+))[\;\s]/g;

  // Private functions
  var parseTags = (tags) => {
    if (!tags) return null;

    var tagDict = {};
    for (var match; (match = TAG_REGEX.exec(tags)) !== null;) {
      var name = match[1].replace(/-(\w)/g, (_, w) => w.toUpperCase());
     
      if (match[3]) {
        if (match[3].indexOf(',') > 0)
          tagDict[name] = match[3].split(',');
        else if ("true" == match[3]) tagDict[name] = 1;
        else if ("false" == match[3]) tagDict[name] = 0;
        else tagDict[name] = match[3];
      }
      else tagDict[name] = parseInt(match[2]);
    }

    return tagDict;
  }

  var parseMessage = (msg) => {
    var rexMsg = MSG_REGEX.exec(msg);
    if (!rexMsg) return { raw: msg };
    return {
      tags: parseTags(rexMsg[1]),
      host: rexMsg[3] || rexMsg[4] || null,
      user: rexMsg[6] || rexMsg[2] || null,
      command: rexMsg[5] || null,
      channel: rexMsg[7] || null,
      payload: rexMsg[8] || null
    };
  }

  // -------------------
  function TwitchChatReader(
    channel,
    onMessageFn = null,
    onOpenFn = null,
    onCloseFn = null
  ) {
    this.channel = channel;
    this.onOpenFn = onOpenFn;
    this.onCloseFn = onCloseFn;
    this.onMessageFn = onMessageFn;
    this.socket = null;
  }

  TwitchChatReader.prototype.connect = function () {
    if (this.socket != null) return;
    this.socket = new WebSocket(IRC_WEBSOCKET);

    // Socket onOpenConnection function
    this.socket.onopen = () => {
      var randId = Math.floor(9e6 * Math.random() + 1e6);
      var botName = "justinfan" + randId;

      this.socket.send("NICK " + botName);
      this.socket.send("CAP REQ :twitch.tv/commands twitch.tv/tags");
      this.socket.send("JOIN #" + this.channel);

      if (this.onOpenFn) this.onOpenFn(botName);
    };

    // Socket onCloseConnection function
    this.socket.onclose = (event) => {
      if (this.onCloseFn)
        this.onCloseFn(event.code, event.reason, event.wasClean);
    };

    // Socket onMessageReceived function
    this.socket.onmessage = (event) => {
      event.data
        .trim()
        .split("\r\n")
        .forEach((str) => {
          var data = parseMessage(str);

          if (data.command == "PING")
            this.socket.send("PONG :" + data.payload);
          else if (this.onMessageFn)
            this.onMessageFn(data, data.command == "PRIVMSG");
          else if (data.command == undefined) console.log(data);
        });
    };
  };

  TwitchChatReader.prototype.close = function () {
    if (this.socket == null) return;
    this.socket.close(1000);
    this.socket = null;
  };

  TwitchChatReader.prototype.send = function (msg) {
    if (this.socket == null) return;
    this.socket.send(msg);
  };

  return (TwitchChatReader.prototype.constructor = TwitchChatReader);
})();

twitchchatreader.min.js

/**
 * MIT License
 * Copyright (c) 2022 Giuseppe Eletto <[email protected]>
 */var TwitchChatReader=function(){var t=/^(?:@(\S+)\ +)?(?::(?:(?:(\w+)!(\S+))|(\S+))\ +)?(?:(\w+)\ *)(?:(\w+)[ =]*)?(?:\#(\w+)\ *)?(?::(.+))?$/m,n=/([\w\+][^\=]+)\=(?:(\d+)|([^\;\s]+))[\;\s]/g,s=t=>{if(!t)return null;for(var s,e={};null!==(s=n.exec(t));){var o=s[1].replace(/-(\w)/g,((t,n)=>n.toUpperCase()));s[3]?s[3].indexOf(",")>0?e[o]=s[3].split(","):"true"==s[3]?e[o]=1:"false"==s[3]?e[o]=0:e[o]=s[3]:e[o]=parseInt(s[2])}return e};function e(t,n=null,s=null,e=null){this.channel=t,this.onOpenFn=s,this.onCloseFn=e,this.onMessageFn=n,this.socket=null}return e.prototype.connect=function(){null==this.socket&&(this.socket=new WebSocket("wss://irc-ws.chat.twitch.tv"),this.socket.onopen=()=>{var t="justinfan"+Math.floor(9e6*Math.random()+1e6);this.socket.send("NICK "+t),this.socket.send("CAP REQ :twitch.tv/commands twitch.tv/tags"),this.socket.send("JOIN #"+this.channel),this.onOpenFn&&this.onOpenFn(t)},this.socket.onclose=t=>{this.onCloseFn&&this.onCloseFn(t.code,t.reason,t.wasClean)},this.socket.onmessage=n=>{n.data.trim().split("\r\n").forEach((n=>{var e,o,l=(e=n,(o=t.exec(e))?{tags:s(o[1]),host:o[3]||o[4]||null,user:o[6]||o[2]||null,command:o[5]||null,channel:o[7]||null,payload:o[8]||null}:{raw:e});"PING"==l.command?this.socket.send("PONG :"+l.payload):this.onMessageFn?this.onMessageFn(l,"PRIVMSG"==l.command):null==l.command&&console.log(l)}))})},e.prototype.close=function(){null!=this.socket&&(this.socket.close(1e3),this.socket=null)},e.prototype.send=function(t){null!=this.socket&&this.socket.send(t)},e.prototype.constructor=e}();

TODO

• Better IRCv3 message parser
• Create an asynchronous version
• Keep it lightweight (~1.6Kb minimized )