stream-wat2.js

#!/usr/bin/env node

const fs = require('fs');

if (!process.argv[2]) {
  console.error('Incorrect parameters');
  console.error('Usage: ./analytics.js <json-file>');
  process.exit(2);
}

function read(onData) {
  return new Promise((resolve, reject) => {
    const rStream = fs.createReadStream(INPUT_PATH, { encoding: 'utf8' });
    rStream.on('end', resolve)
    rStream.on('error', reject)
    rStream.on('data', onData)
  });
}

function main() {
  const INPUT_PATH = process.argv[2];

  return read((data) => {
    throw new Error('Imagine this error was thrown by JSON.parse(data)'); 
  });
}

main()
  .catch(err => {
    console.error('Error happened:', err)
    throw err;
  });