$ mkdir twitter-bot
$ cd twitter-bot

$ yarn init

$ yarn add twitter

$ yarn add dotenv

API_KEY=xxxxxxxxxxx
API_SECRET_KEY=xxxxxxxxxxxx
ACCESS_TOKEN=xxxxxxxxxxxxxxxxxxxxxxxxxxxxx
ACCESS_TOKEN_SECRET=xxxxxxxxxxxxxxxxxxxxxxxxxxxx

require('dotenv').config();

var Twitter = require('twitter');

// 初期化
var client = new Twitter({
  consumer_key: process.env.API_KEY,
  consumer_secret: process.env.API_SECRET_KEY,
  access_token_key: process.env.ACCESS_TOKEN,
  access_token_secret: process.env.ACCESS_TOKEN_SECRET
})

// 最大取得件数を指定。200がMAXだそうです
const count = 200

// Twitter API 実行
function fetchUser(url, params) {
  return new Promise((resolve, reject) => {
    client.get(url, params)
      .then(list => {
        // 連打すると制限に引っかかりレスポンスがかえってこなくなるので、3秒待つことにした
        setTimeout(() => {
          resolve(list)
        }, 3000)
      })
      .catch(error => {
        reject(error)
      })
  })
}


// 最高200件までしかとれないので、cursorを使って先のデータがなくなるまで
// Promise で 繰り返しデータを取得する
async function getUser(url) {
  var users = []
  var next_cursor = 1
  var params = {count: count}

  while(next_cursor != 0) {
    const list = await fetchUser(url, params)

    for (user of list.users) {
      users.push(user.name)
    }
    next_cursor = list.next_cursor
    params = {count: count, cursor: next_cursor}
    console.log(next_cursor)
  }

  return users
}

// フォローとフォロワーの配列の差分を返す
function getDiff(x, y, ope){
  x.forEach(item =>{
    if(!y.includes(item)){
      ope(item);
    }
  })
}

// promiseで実装
async function diff() {
  var friends = []
  var followers = []

  await getUser('friends/list').then((r) => {
    friends = r
  })
  await getUser('followers/list').then((r) => {
    followers = r
  })

  getDiff(friends, followers, item => console.log('friends include and followers do not inclode :' +item));
}

// 実行
diff()

process.on('unhandledRejection', console.dir);

$ node index.js

> friends include and followers do not inclode :Newton Faulkner
> friends include and followers do not inclode :John Butler Trio
> friends include and followers do not inclode :Dropbox
> friends include and followers do not inclode :ARATA ISHIKAWA
> friends include and followers do not inclode :孫正義
> friends include and followers do not inclode :Google Devs Japan
> friends include and followers do not inclode :Lotus
> friends include and followers do not inclode :STS9

[ { message: 'Rate limit exceeded', code: 88 } ]