import fs from 'fs'
import { Transform } from 'stream'
import JSONStream from 'JSONStream'

// Custom transform stream
const transformer = new Transform({
  objectMode: true,
  transform(jsonItem, encoding, callback) {
    // your logic goes here...
    // const updatedItem = {}

    callback(null, updatedItem)
   }
})

const input = fs.createReadStream('./raw-input.json', 'utf8')
const output = fs.createWriteStream('processed-output.json', 'utf8')

input
  .pipe(JSONStream.parse('*')) // JSON structure parser pattern
  .pipe(transformer) // Process data
  .pipe(JSONStream.stringify()) // Convert it back to JSON
  .pipe(output) // save the result