Creating Migrations with Bulk upload in mongoDB

resources.js

require('dotenv').config()
const { MongoClient, ObjectID } = require('mongodb')

const url = process.env.MASTER_DB_URI
const documents = require('./data.json')

const connect = dbUrl => new Promise((resolve, reject) => {
  MongoClient.connect(dbUrl, (err, db) => {
    if (err) reject(err)
    else resolve(db)
  })
})
const createCollection = (db, collectionName) => new Promise((resolve, reject) => {
  db.createCollection(collectionName, (err, collection) => {
    if (err) reject(err)
    else resolve(collection)
  })
})

const task = (db, collection, docs) => {
  if (!db || !collection || !docs) {
    throw new Error('fields missing')
  }
  const bulk = collection.initializeUnorderedBulkOp()
  docs.forEach((_doc) => {
    const doc = _doc
    if (doc._id && typeof doc._id === 'string') {
      doc._id = ObjectID(doc._id)
    }
    if (doc.parentSpecialties) {
      doc.parents = doc.parents.map(id => ObjectID(id))
    }
    bulk.insert(doc)
  })
  return new Promise((resolve, reject) => {
    bulk.execute((err, result) => {
      if (err) reject(err)
      else resolve(result)
    })
  })
}

exports.up = async function up (next) {
  try {
    const db = await connect(url)
    const collection = await createCollection(db, 'items')
    await task(db, collection, documents)
    next()
  } catch (err) {
    throw err
  }
}

exports.down = function down (next) {
  next()
}