Google speech to text node js code

// Imports the Google Cloud client library
const speech = require('@google-cloud/speech');
const fs = require('fs');

var speechToText = function(filetoProcess , callback){

// Creates a client
const client = new speech.SpeechClient();

// The name of the audio file to transcribe
const fileName = filetoProcess;

// Reads a local audio file and converts it to base64
const file = fs.readFileSync(fileName);
const audioBytes = file.toString('base64');

// The audio file's encoding, sample rate in hertz, and BCP-47 language code
const audio = {
  content: audioBytes,
};
const config = {
  encoding: 'LINEAR16',
  sampleRateHertz: 8000,
  languageCode: 'en-IN',
  profanityFilter: true,
  // speechContexts: {
  //     phrases:["yes","no"]
  //    },
  metadata: {
           interactionType: "VOICEMAIL",
           //industryNaicsCodeOfAudio: 23810,
           microphoneDistance: "NEARFIELD",
           originalMediaType: "AUDIO",
           numberOfSpeakers: "ONE_SPEAKER",
           //recordingDeviceType: "OTHER_INDOOR_DEVICE",
           //recordingDeviceName: "Polycom SoundStation IP 6000",
           //originalMimeType: "audio/mp3",
           //obfuscatedId: "11235813",
           //audioTopic: "questions about landmarks in NYC"
       }
};
const request = {
  audio: audio,
  config: config,
};

// Detects speech in the audio file
client
  .recognize(request)
  .then(data => {
    const response = data[0];
    const transcription = response.results
      .map(result => result.alternatives[0].transcript)
      .join('\n');
    console.log(`Transcription: ${transcription}`);
    callback(transcription);
  })
  .catch(err => {
    console.error('ERROR:', err);
  });
}

module.exports.speechToText = speechToText;