write and read string to mongo

index.js

import mongoose from 'mongoose';
import dotenv from 'dotenv';
import { Readable } from 'stream'

let bucket;

const envConfig = dotenv.config();
if (envConfig.error) {
  console.log('.env file does not loaded');
  throw envConfig.error;
}

mongoose.connect(process.env.MONGO_PATH, {
  useNewUrlParser: true,
  useUnifiedTopology: true,
  useCreateIndex: true,
}).then((result) => {
  console.log(`MongoDB connection granted`);

  bucket = new mongoose.mongo.GridFSBucket(db.db);

  run()

}).catch(error => console.log(`There is troubles with connecting to MongoDB ${error}`));


const db = mongoose.connection;
db.on('error', console.error.bind(console, 'connection error:'));
db.once('open', function () {
  console.log('success connect');
});


const createMessage = () => ({
  phone_number: '+380955555555',
  meta: {
    phone_number: '+380955555555',
    custom: 'custom',
    first_name: 'first',
    last_name: 'last',
  },
  rate: 1.1,
  mccMnc: 123,
  text: 'text',
});

const generateLR = (messageQuantity) => {
 return JSON.stringify({
    broadcast_id: '1',
    messages: Array(messageQuantity).fill(createMessage()),
    senders: ['sender1', 'sender2'],
    links: ['link1', 'link2'],
    unsubscription_list_ids: [1, 2, 3],
  });
};

const run = async () => {

  const writeToMongo = async (params,data) => {
    const { filename } = params;
    const uploadStream = bucket.openUploadStream(filename);

    return new Promise((resolve, reject) => {
      Readable.from(data, {encoding: 'utf8'})
        .pipe(uploadStream)
        .on('error', () => {
          console.log('error');
          reject(false)
        })
        .on('finish', () => {
          console.log('done!');
          resolve(true)
        });
    });
  };

  const readFromMongo = async (params) => {
    const { filename } = params;
    return new Promise((resolve, reject) => {
      let data = '';
      const downloadStream = bucket.openDownloadStreamByName(filename);
      downloadStream.on('data', (chunk) => data += chunk)
        .on('end', () => resolve(data))
        .on('error', () => reject('SOME ERROR HAPPEN'))
    })
  };

  let a = await writeToMongo({ filename: 'filename2.txt' }, generateLR(1));
  console.log('isSuccess?: ', a);
  let b = await readFromMongo({ filename: 'filename2.txt' });
  console.log('readResult', b);

  return true;
};