CSV to Mongo Stream musings

stream.js

fs.createReadStream(argv.heart)
  .pipe(csv.parse({ objectMode: true }))
  .pipe(csv.transform({
    header: columns => {
      const properties = {
        Start: 'start',
        End: 'end',
        'Heart Rate (count/min)': 'heartRate',
      }
      return columns.map(column => properties[column] || column)
    },
    row: row => {
      const properties = {
        start: date => new Date(date),
        end: date => new Date(date),
        heartRate: rate => Number(rate),
      }
      return row.map(({column, value}) => properties[column](value) || value)
    },
  }))
  .pipe(MongoStream.insert({
    url: '',
    db: '',
    collection: '',
  }))
  .on('init', (collection, next) => {
    return collection.drop().then(next)
  })
  .on('end', (collection, next) => {
    return collection.count({}).then(count => console.log(count)).then(next)
  })