Code example of for in and forEach

user.for_in.service.js

/*
 * Find first manager
 */
function findFirstManager(employees) {
  let manager = {};
  employees.forEach((employee) => {
    if (employee.role === "Manager") {
      manager = employee;
      // return or break won't work here, so it will continue to loop till the end
    }
  });

  // It will return most recent manager NOT first
  return manager;
}

/*
 * Count HRs
 */
function countHRs(employees) {
  let count = 0;
  // It will loop over employees internal meta properties also
  for (let i in employees) {
    if (employees[i].role === "HR") count++;
  }

  return count;
}