bulkWriteValidation.js

const mongoose = require('mongoose')
const Promise = require('bluebird')
mongoose.Promise = Promise

const mixinBulkWriteValidation = require('./mixinBulkWriteValidation')

mongoose.connect('mongodb://localhost/bulk_update_validation_test', { useMongoClient: true })
const connection = mongoose.connection
const Schema = mongoose.Schema

const schema = new Schema({
  name: String
})

const WithoutValidation = mongoose.model('WithoutValidation', schema)

const WithValidation = mixinBulkWriteValidation(
  mongoose.model('WithValidation', schema)
)

const updateOne = (document, update) => {
  return {
    updateOne: {
      filter: {
        _id: document._id
      },
      update: {
        $set: update
      }
    }
  }
}

async function run () {
  await connection.dropDatabase()

  const withoutValidationBefore = await WithoutValidation.create({
    name: 'Some name'
  })
  const withValidationBefore = await WithValidation.create({
    name: 'Some name'
  })
  await WithoutValidation.bulkWrite([
    updateOne(withoutValidationBefore, { name: 'Some other name', foo: 'bar' })
  ])
  await WithValidation.bulkWrite([
    updateOne(withValidationBefore, { name: 'Some other name', foo: 'bar' })
  ])

  const withoutValidationAfter = await WithoutValidation.findOne().lean()
  const withValidationAfter = await WithValidation.findOne().lean()
  console.log(
    'withoutValidationBefore',
    JSON.stringify(withoutValidationBefore, null, 2)
  )
  console.log(
    'withoutValidationAfter',
    JSON.stringify(withoutValidationAfter, null, 2)
  )
  console.log(
    'withValidationBefore',
    JSON.stringify(withValidationBefore, null, 2)
  )
  console.log(
    'withValidationAfter',
    JSON.stringify(withValidationAfter, null, 2)
  )

  return connection.close()
}

run().catch(console.error)

mixinBulkWriteValidation.js

const _ = require('lodash')

module.exports = model => {
  const originalBulkWrite = model.bulkWrite
  model.bulkWrite = function () {
    arguments[0] = removeKeysNotInSchema(arguments[0], model)
    return originalBulkWrite.apply(model, arguments)
  }
  return model
}

const removeKeysNotInSchema = (ops, model) =>
  _.map(ops, op => {
    const $set = _.get(op, 'updateOne.update.$set')
    if (!$set) return op
    const updateKeys = _.keys($set)
    const schemaKeys = _.keys(model.schema.paths)
    const keysNotInSchema = _.difference(updateKeys, schemaKeys)
    _.each(keysNotInSchema, keyNotInSchema => {
      delete op.updateOne.update.$set[keyNotInSchema]
    })
    return op
  })

output.txt

node bulkUpdateValidation.js

withoutValidationBefore {
  "__v": 0,
  "name": "Some name",
  "_id": "5ae9f4e8219d9b1e34ab9258"
}
withoutValidationAfter {
  "_id": "5ae9f4e8219d9b1e34ab9258",
  "name": "Some other name",
  "__v": 0,
  "foo": "bar"
}
withValidationBefore {
  "__v": 0,
  "name": "Some name",
  "_id": "5ae9f4e8219d9b1e34ab9259"
}
withValidationAfter {
  "_id": "5ae9f4e8219d9b1e34ab9259",
  "name": "Some other name",
  "__v": 0
}

Removes keys / values that aren't part of a Mongoose model's schema during a Model.bulkWrite.