How to get the value from an array and assign to object of arrays?

February 4, 2022

I am trying to get the values from an array and assign to an array of objects as a new property.
The array of objects:

const employees = [
  {
    firstName: "Ana",
    lastName: "Rosy"
  },
  {
    firstName: "Zion",
    lastName: "Albert"
  },
  {
    firstName: "John",
    lastName: "Doe"
  }
];

An array

const ages = [30, 60, 45]

Desired result

const employees = [
  {
    firstName: "Ana",
    lastName: "Rosy",
    age:30
  },
  {
    firstName: "Zion",
    lastName: "Albert",
    age:60
  },
  {
    firstName: "John",
    lastName: "Doe",
    age:45
  }
];

I tried something like this

const employeesWithAge = (ages) => {
  return employees.map((row) => {
    return {
      ...row,
      age: ages
    };
  });
};
const result = employeesWithAge(ages);
console.log("result", result);

But it adds the entire array of ages to the employees array of objects.
Any help will be appreciated

>Solution :

You can use Array.prototype.map() for this. Use the spread syntax (...) on the current element to copy the properties into a new object, then add the age property based on the ages array, using .map() callback’s second parameter (the current index).

employees.map((employee, i) => ({...employee, age: ages[i]}));

Live example:

const employees = [{
    firstName: "Ana",
    lastName: "Rosy"
  },
  {
    firstName: "Zion",
    lastName: "Albert"
  },
  {
    firstName: "John",
    lastName: "Doe"
  }
];

const ages = [30, 60, 45];

const result = employees.map((employee, i) => ({ ...employee, age: ages[i] }));

console.log(result);