Twitch Activity Alerts Example

alerts.ts

class PubSub {
  private url: string = "wss://pubsub-edge.twitch.tv";
  protected connection: WebSocket;
  private heartbeat: number;
  private topic: string;

  constructor(channel: number) {
    this.topic = `dashboard-activity-feed.${channel}`;

    this.connection = new WebSocket(this.url);
    this.connection.onopen = this.onOpen.bind(this);
    this.connection.onmessage = this.onMessage.bind(this);
    this.connection.onclose = this.onClose.bind(this);
  }

  private sendPing(): void {
    this.connection.send(JSON.stringify({ type: "PING" }));
  }

  private listen(): void {
    this.connection.send(
      JSON.stringify({
        type: "LISTEN",
        data: { topics: [this.topic] }
      })
    );
  }

  private onOpen(): void {
    console.log("connection opened");
    this.sendPing();
    this.listen();
    this.heartbeat = setInterval(this.sendPing.bind(this), 1000 * 120);
  }

  private onClose(): void {
    console.warn("connection closed");
    clearInterval(this.heartbeat);
  }

  private sendAlert(title: string, message: string): void {
    console.log("ALERT!", title, message);
  }

  private onMessage({ data: msg }: any): void {
    let title: string = "";
    let message: string = "";

    msg = JSON.parse(msg);
    if (msg.type === "MESSAGE" && msg.data.topic === this.topic) {
      let data = JSON.parse(msg.data.message);
      switch (data["type"]) {
        case "follow":
          title = `New Follower!`;
          message = data["follower"]["display_name"];
          break;

        case "subscription":
        case "prime_resubscription_sharing":
        case "resubscription_sharing":
          title = `New Subscriber! - ${
            data["subscription_cumulative_tenure_months"]
          } Months`;
          message = data["subscriber"]["display_name"];
          break;

        case "raiding":
          title = `${data["raider"]["display_name"]} started raiding`;
          message = `welcome ${data["raiding_viewer_count"]} viewers!`;
          break;

        case "host_start":
          title = `${data["host"]["display_name"]} started raiding`;
          message = `asd`;
          break;

        case "bits_usage":
          title = `${data["bits_user"]["display_name"]} cheered!`;
          message = `${data["bits_amount"]}`;
          break;

        default:
          break;
      }
      if (title !== "") this.sendAlert(title, message);
    }
  }
}

export default PubSub;

index.ts

import PubSub from "./pubsub";

new PubSub(37402112); // 37402112 = shroud