Notification permissions system with Permer

notifications.ts

import { Permer } from "permer";

const permer = new Permer(["web", "email"]);

type NotificationSettings = {
  user_id: number;
  review_comment: number;
  user_likes_review: number;
  user_comment_review: number;
  user_like_list: number;
  user_follow: number;
};

type EventName = keyof Omit<NotificationSettings, "user_id">;

type User = {
  id: number;
  username: string;
  email: string;
  password: string;
};

const users: User[] = [
  {
    id: 1,
    email: "alistair@edge.gg",
    username: "alistair",
    password: "pwd1234secure",
  },
  {
    id: 2,
    email: "benja@edge.gg",
    username: "benja",
    password: "1234568re8ysdfh",
  },
];

const table: NotificationSettings[] = [
  {
    user_id: users[0].id,
    review_comment: permer.toPermissionsInteger(["email", "web"]),
    user_likes_review: permer.toPermissionsInteger(["web"]),
    user_comment_review: permer.toPermissionsInteger(["email", "web"]),
    user_like_list: permer.toPermissionsInteger([]),
    user_follow: permer.toPermissionsInteger(["email"]),
  },
  {
    user_id: users[1].id,
    review_comment: permer.toPermissionsInteger(["web"]),
    user_likes_review: permer.toPermissionsInteger(["email"]),
    user_comment_review: permer.toPermissionsInteger(["email"]),
    user_like_list: permer.toPermissionsInteger(["web", "email"]),
    user_follow: permer.toPermissionsInteger(["web"]),
  },
];

export const notificationManager = new (class NotificationEmitter {
  sendWebNotification(user: User) {
    console.log("Sending a web notif to", user.email);
  }

  sendEmailNotification(user: User) {
    console.log("Sending an email to", user.email);
  }

  sendEvent(event_name: EventName) {
    for (const user of users) {
      const settings = table.find((row) => {
        return row.user_id === user.id;
      });

      const transports = permer.toPermissionList(settings[event_name]);

      for (const transport of transports) {
        switch (transport) {
          case "web":
            this.sendWebNotification(user);
            break;
          case "email":
            this.sendEmailNotification(user);
            break;
        }
      }
    }
  }
})();

notificationManager.sendEvent("user_follow");