employeeRegions.js

const employeeRegions = [
  [
    {
      name:   'Mike',
      age:    23,
      title:  'engineer',
      remote: false,
    },
    {
      name:   'Liz',
      age:    20,
      title:  'engineer',
      remote: true,
    },
    {
      name:   'Chris',
      age:    102,
      title:  'president',
      remote: true,
    },
    {
      name:   'Chuloo',
      age:    27,
      title:  'manager',
      remote: false,
    },
  ],
  [
    {
      name:   'Michelle',
      age:    65,
      title:  'engineer',
      remote: true,
    },
    {
      name:   'Sam',
      age:    25,
      title:  'manager',
      remote: false,
    },
    {
      name:   'Ivy',
      age:    26,
      title:  'engineer',
      remote: false,
    },
    {
      name:   'Nick',
      age:    32,
      title:  'engineer',
      remote: true,
    },
  ]
];

/**
 * * Return an array of employees.
 * * Do not include any employees who are remote.
 * * Add a field "region" to each employee object. The region value should be
 * ** the string "Region " together with the index of the group plus one
 * ** "Region 1" (for index 0).
 *
 * @param {array[]} employeeRegions
 * @returns {array}
 */
function transformGroups(employeeRegions) {
    return employeeRegions.map((group, index) => {
      return group.filter(employee => {
        if (!employee.remote) {
          employee.region = `Region ${index + 1}`;
          return employee;
        }
      });
    })
    .flat();
}