java script function for filling a list

Question

I wrote a function that enters personal information into empty list and save them. I want to add one by one but if first name and last name have entered before, show me "user has been added before" and does not add repeated user.my function does not work and i do not understand why? list is still empty!!

var personalInfo = [];

function addEmployee(firstName, lastName, hourPerMonth, salaryPerHour) {
  if (hourPerMonth > 160) return 'hourPerMonth is too much';
  
    personalInfo.push({
      'firstName': firstName,
      'lastName': lastName,
      'hourPerMonth': hourPerMonth,
      'salaryPerHour': salaryPerHour
    });

  for (let index = 0; index < personalInfo.length; index++) {
    let item = personalInfo[index];
    if (item.firstName !== firstName && item.lastName !== lastName) {
      personalInfo.push({
        'firstName': firstName,
        'lastName': lastName,
        'hourPerMonth': hourPerMonth,
        'salaryPerHour': salaryPerHour
      });
    }
  }
  return personalInfo;
}


//for example:
addEmployee('alex', 'ortemi', 134, 23); //ok
addEmployee('olivia', 'zikari', 144, 26); //ok
addEmployee('alex', 'ortemi', 132, 13); // error : user has been added before

any solution would be my appreciate

I have tried couple of solutions but i did not get answer

Answer 1

This should do

let personalInfo = [];

//adds user to DB
const addEmployee = (
    firstName,
    lastName,
    workHoursPerMonth,
    salaryPerHour,
    dataBase = personalInfo
) => {
    let isDuplicate = false;
    /*loop over the DB to check if firstName and lastName comb. has a duplicate*/
    for (let i = 0; i < dataBase.length; i++) {
        // check if the input firstName and lastName combination match dataBase[i] element
        if (
            workHoursPerMonth < 160 &&
            (dataBase.length === 0 ||
                !(
                    dataBase[i].firstName === firstName &&
                    dataBase[i].lastName === lastName
                ))
        ) {
        } else {
            isDuplicate = true;
            break;
        }
    }
    if (!isDuplicate) {
        dataBase.push({});
        dataBase[dataBase.length - 1].firstName = firstName;
        dataBase[dataBase.length - 1].lastName = lastName;
        dataBase[dataBase.length - 1].workHoursPerMonth = workHoursPerMonth;
        dataBase[dataBase.length - 1].salaryPerHour = salaryPerHour;
        isDuplicate = true;
        return `user '${firstName} ${lastName}' was successfully added.`;
    } else {
        return `We couldn't Add user: '${firstName} ${lastName}' ! perhaps cause of duplicated data or irregular work hour`;
    }
};

addEmployee("alex", "ortemi", 134, 23); //ok
addEmployee("olivia", "zikari", 144, 26); //ok
addEmployee("alex", "ortemi", 132, 13); // the function filters that succesfully
console.log(personalInfo);