Sort an Array of Objects in JavaScript. How to sort an array of objects by the values of the object’s properties

Sort an Array of Objects in JavaScript.js

//-------------------------------------------------------
// Sort an Array of Objects in JavaScript
// 
// To sort an array of objects, you use the sort() method 
//  and provide a comparison function that determines
//  the order of objects.
//-------------------------------------------------------

//-------------------------------------------------------
// Suppose that you have an array of employee objects as follows:
let employees = [
    {
        firstName: 'John',
        lastName: 'Doe',
        age: 27,
        joinedDate: 'December 15, 2017'
    },

    {
        firstName: 'Ana',
        lastName: 'Rosy',
        age: 25,
        joinedDate: 'January 15, 2019'
    },

    {
        firstName: 'Zion',
        lastName: 'Albert',
        age: 30,
        joinedDate: 'February 15, 2011'
    }
];

//-------------------------------------------------------
// Sort an array of objects by numbers
// The following statement snippet sorts the employees
//  array by ages in ascending order:
employees.sort((a, b) => {
    return a.age - b.age;
});

// To display the employees, you use the forEach() method:
employees.forEach((e) => {
    console.log(`${e.firstName} ${e.lastName} ${e.age}`);
});
// Ana Rosy 25
// John Doe 27
// Zion Albert 30

//-------------------------------------------------------
// To sort the employees by ages in descending order,
//    you just need to reverse the order in the comparison function
employees.sort((a, b) => b.age - a.age);

//--- And the following code shows the output:
employees.forEach((e) => {
    console.log(`${e.firstName} ${e.lastName} ${e.age}`);
});
// Zion Albert 30
// John Doe 27
// Ana Rosy 25

//-------------------------------------------------------
// The following snippet shows how to sort employees by first names
//   in descending order case-insensitively:
employees.sort((a, b) => {
    let fa = a.firstName.toLowerCase(),
        fb = b.firstName.toLowerCase();

    if (fa < fb) {
        return -1;
    }
    if (fa > fb) {
        return 1;
    }
    return 0;
});

//--- And the following code shows the output:
employees.forEach((e) => {
    console.log(`${e.firstName} ${e.lastName}`);
});
// Ana Rosy
// John Doe
// Zion Albert    

//-------------------------------------------------------
// Sort an array of objects by dates
// To sort the employees by joined dates, you need to:
//  - Convert the joined dates from strings to date objects.
//  - Sort the employees by dates.
employees.sort((a, b) => {
    let da = new Date(a.joinedDate),
        db = new Date(b.joinedDate);
    return da - db;
});

//--- And the following code shows the output:
employees.forEach((e) => {
    console.log(`${e.firstName} ${e.lastName} ${e.joinedDate}`);
});
// Zion Albert Feb 15, 2011
// John Doe December 15, 2017
// Ana Rosy January 15, 2019
//-------------------------------------------------------