birthday-bot.js

const Facebook = require("facebook-chat-api");
const FileSystem = require("fs");

const BIRTHDAY_WISHES = require("./birthday-wishes.json");
const { FACEBOOK_USERNAME, FACEBOOK_PASSWORD, FORCE_LOGIN=true } = process.env;

const getRandomWish = () => {
  let randomWish =
    BIRTHDAY_WISHES[Math.floor(Math.random() * BIRTHDAY_WISHES.length)];
  return randomWish;
};

const getFriendsWithBirthdays = friends => {
  let friendsWithBirthdays = friends.filter(friend => {
    return friend.isBirthday === true && friend.userID !== "0";
  });
  return friendsWithBirthdays;
};

const getCredentials = () => {
  const stateFileExists = FileSystem.existsSync("appstate.json");
  const forceLogin = FORCE_LOGIN === "true" ? true : false;
  if (stateFileExists && !forceLogin) {
    const appState = FileSystem.readFileSync("appstate.json");
    return { appState };
  } else {
    return {
      email: FACEBOOK_USERNAME,
      password: FACEBOOK_PASSWORD
    };
  }
};

let wishFriendsOnTheirBirthday = () => {
  Facebook(getCredentials(), (error, instance) => {
    if (error) throw error;
    const sendWishes = friend => {
      let { firstName, userID } = friend;
      let body = `Hello ${firstName}, ${getRandomWish()}.`;
      instance.sendMessage({ body }, userID, (error, { timestamp }) => {
        if (error) throw error;
        console.log(
          `Sent Birthday Wishes to ${firstName} on ${new Date(
            timestamp
          ).toDateString()}.`
        );
      });
    };
    FileSystem.writeFileSync(
      "appstate.json",
      JSON.stringify(instance.getAppState())
    );
    instance.getFriendsList((error, internetFriends) => {
      if (error) throw error;
      let friendsWithBirthdays = getFriendsWithBirthdays(internetFriends);
      friendsWithBirthdays.forEach(friend => {
        sendWishes(friend);
      });
    });
  });
};