index.js

require('dotenv').config()
const { MongoClient } = require('mongodb')
const { getAllLikes } = require('./lib/get-likes')
let { saveLikes, savePage, getLowest } = require('./lib/db')

const { MONGO_URL } = process.env

;(async function() {
  const db = await MongoClient.connect(MONGO_URL)
  const Pages = db.collection('pages')
  const Likes = db.collection('likes')
  await Likes.ensureIndex({user_id: 1, page_id: 1}, { unique: true })

  getLowest = getLowest.bind({ Pages })
  savePage = savePage.bind({ Pages })
  saveLikes = saveLikes.bind({ Likes })

  ;(async function restart () {
    const lowest = await getLowest()
    if (!lowest) {
      console.log('****** my work here is done ******')
      return
    }

    console.log('------------------------------')
    console.log(`  Getting likes from ${lowest.pageId}`)

    const { likeLink, postLink, lastDate, likes } = await getAllLikes(lowest.likeLink, lowest.postLink, lowest.lastDate, [])
    const savedLikes = await saveLikes(likes, lowest._id)
    const savedRatio = Math.round((savedLikes / likes.length) * 100) / 100
    let counter = lowest.counter + savedLikes
    await savePage(likeLink, postLink, lastDate, counter, lowest._id)

    console.log(`  fetched (${likes.length}) / new (${savedLikes}) = ${savedRatio}`)
    console.log('------------------------------\n')

    restart()
  })()
})()

process.on('unhandledRejection', error => {
  console.log('unhandledRejection', error)
});