Reduce method with data from file

import fs from 'fs'

var output = fs.readFileSystem('example.txt', 'utf8')
  .trim()
  .split('\n')
  .map(line => line.split('\t'))
  .reduce((customers, line) => {
    customers[line[0]] =  customers[line[0]] || []
    customers[line[0]].push({
      name: line[1],
      smth: line[2]
    });
    return customers;
  },{});
  
/*
* Data example:
*   mark name smth
*   mark name smth
*   mark name smth
*   jhon  name smth
*   jhon  name smth
*/