Get a collection of movie titles using native Node.js

getMovieTitles.js

/*
  Given a string `substr`, getMovieTitles() must perform the following tasks:
    1. Query https://jsonmock.hackerrank.com/api/movies/search/?Title=substr (replace substr). 
    2. Initialize the titles array to store total string elements. Store the Title of each movie meeting the search criterion in the titles array.
    3. Sort titles in ascending order and return it as your answer.
*/

const https = require('https')
const log = console.log

const getTotalPages = (url, callback) => {
  https.get(url, res => {
    let data = ''

    res.on('data', chunk => data += chunk)

    res.on('end', () => {
      return callback(null, JSON.parse(data).total_pages)
    })
  }).on('error', err => {
    return callback(err, null)
  })
}

const getMovieTitlesHelper = (urls, callback) => {
  let titles = new Array()
  let counter = 1

  urls.forEach(url => {
    https.get(url, res => {
      let data = ''

      res.on('data', chunk => data += chunk)

      res.on('end', () => {
        const movies = JSON.parse(data).data

        movies.forEach(movie => titles.push(movie.Title))

        if (counter === urls.length) {
          return callback(null, titles)
        }
        counter++
      })
    }).on('error', err => {
      return callback(err, null)
    })
  })
}

/*
 * Complete the function below.
 * Use console.log to print the result, you should not return from the function.
 */
const getMovieTitles = substr => {
  if (substr === '') {
    return null
  }

  const url = `https://jsonmock.hackerrank.com/api/movies/search/?Title=${substr}`
  getTotalPages(url, (err, totalPages) => {
    if (err) {
      log('Error getting total number of available pages:', err)
    } else {
      const urls = new Array()
      for (let pageNumber = 1; pageNumber <= totalPages; pageNumber++) {
        urls.push(`${url}&page=${pageNumber}`)
      }
      getMovieTitlesHelper(urls, (err, titles) => {
        if (err) {
          log('Error retrieving movies titles:', err)
        } else {
          titles.sort().forEach(title => log(title))
        }
      })
    }
  })
}

getMovieTitles('spiderman')
/* =>
Amazing Spiderman Syndrome
Fighting, Flying and Driving: The Stunts of Spiderman 3
Hollywood's Master Storytellers: Spiderman Live
Italian Spiderman
Spiderman
Spiderman
Spiderman 5
Spiderman and Grandma
Spiderman in Cannes
Superman, Spiderman or Batman
The Amazing Spiderman T4 Premiere Special
The Death of Spiderman
They Call Me Spiderman
*/

I’m getting a runtime error
Cannot read property of results.lenght