Sort an Array of Objects in JavaScript

Summary: in this tutorial, you will learn how to sort an array of objects by the values of the object’s properties.

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'
    }
];
Code language: JavaScript (javascript)

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;
});
Code language: JavaScript (javascript)

To display the employees, you use the forEach() method:

employees.forEach((e) => {
    console.log(`${e.firstName} ${e.lastName} ${e.age}`);
});
Code language: JavaScript (javascript)

Output:

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. For example:

employees.sort((a, b) => b.age - a.age);

employees.forEach((e) => {
    console.log(`${e.firstName} ${e.lastName} ${e.age}`);
});
Code language: JavaScript (javascript)

Output:

Zion Albert 30
John Doe 27
Ana Rosy 25

Sort an array of objects by strings

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;
});
Code language: JavaScript (javascript)

In this example:

• First, convert the names of employees to lowercase.
• Second, compare names and return -1, 1 and 0, depending on the string comparison.

The following code shows the output:

employees.forEach((e) => {
    console.log(`${e.firstName} ${e.lastName}`);
});
Code language: JavaScript (javascript)

Output:

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.

The following code illustrates the idea:

employees.sort((a, b) => {
    let da = new Date(a.joinedDate),
        db = new Date(b.joinedDate);
    return da - db;
});
Code language: JavaScript (javascript)

And the following code shows the output:

employees.forEach((e) => {
    console.log(`${e.firstName} ${e.lastName} ${e.joinedDate}`);
});
Code language: JavaScript (javascript)

Output:

Zion Albert Feb 15, 2011
John Doe December 15, 2017
Ana Rosy January 15, 2019

In this tutorial, you have learned how to sort an array of objects by the values of the object’s properties.