Master the Art of Sorting Array of Objects in JavaScript – with Real Code Examples

Table of content

  1. Introduction
  2. Basics of Sorting
  3. Sorting Arrays of Primitive Data Types
  4. Sorting Arrays of Objects: Simple Cases
  5. Sorting Arrays of Objects: Advanced Cases
  6. Real Code Examples
  7. Best Practices for Sorting Arrays of Objects
  8. Conclusion

Introduction

Sorting arrays is a fundamental data manipulation skill in programming, and it is especially important for JavaScript developers. In JavaScript, arrays are a portable and versatile way of storing data. You can store any number of items in an array, and those items can be of any data type: strings, numbers, Booleans, objects, arrays, or even functions. Moreover, when working with arrays of objects, sorting them is critical for a robust and reliable application.

Sorting arrays of objects in JavaScript can be a little tricky because, unlike sorting arrays of primitive values—such as numbers or strings—sorting arrays of objects requires you to define a sorting criterion or key. A sorting criterion is a rule or function that tells the sorting algorithm how to sort the objects based on their properties. The sorting criterion could be based on any of the object's properties or a combination of them.

In this article, we'll explore the different ways of sorting arrays of objects in JavaScript, starting with the most basic method and working our way up to more advanced techniques. We'll also provide you with real code examples so that you can see how each method works in practice. By the end of this article, you'll have a deep understanding of how to sort arrays of objects in JavaScript and how to apply that knowledge to your own projects.

Basics of Sorting

Sorting is an essential task in programming that helps us arrange data in a specific order based on a particular criterion. In JavaScript, we use the sort() method to sort arrays. The sort() method sorts the elements of an array in place and returns the sorted array. By default, the sort() method sorts the elements in ascending order.

Let's say we have an array of numbers arr = [5, 2, 8, 1, 9]. We can sort this array in ascending order using the sort() method as follows:

arr.sort(); // outputs [1, 2, 5, 8, 9]

But what if we wanted to sort the array in descending order instead? We can achieve this by passing a compare function to the sort() method. The compare function takes two parameters, a and b, and returns a negative value if a should come before b, a positive value if a should come after b, and 0 if they are equal.

Here's an example:

arr.sort(function(a, b) {
   return b - a;
}); // outputs [9, 8, 5, 2, 1]

In the example above, we passed a compare function to the sort() method that compares the numbers in the array in descending order. The function subtracts a from b, so if a is greater than b, the result will be negative, which means that a should come before b in the sorted array.

Sorting arrays of objects requires a slightly different approach. We need to specify the property by which we want to sort the objects. We will cover this in more detail in later subtopics.

Sorting Arrays of Primitive Data Types

Sorting an array of primitive data types in JavaScript is a fairly simple task. You can use the sort() method to sort an array of numbers, strings, or boolean values. The sort() method can also be used to sort an array of mixed data types.

Sorting an Array of Numbers

To sort an array of numbers in ascending order, you can use the sort() method without any arguments. This is because when the sort() method is used without any arguments, it sorts the items in the array as strings.

let numbers = [42, 10, 56, 7, 15];
numbers.sort(); // [10, 15, 42, 56, 7]

As you can see, the numbers are sorted as strings, which is not what we want. To sort the numbers as actual numbers, you can use a compare function that subtracts one number from another. This function will sort the numbers in ascending order.

let numbers = [42, 10, 56, 7, 15];
numbers.sort((a, b) => a - b); // [7, 10, 15, 42, 56]

Sorting an Array of Strings

To sort an array of strings in alphabetical order, you can use the sort() method without any arguments. This is because when the sort() method is used without any arguments, it sorts the items in the array alphabetically.

let fruits = ['banana', 'apple', 'orange', 'pear'];
fruits.sort(); // ['apple', 'banana', 'orange', 'pear']

Sorting an Array of Boolean Values

To sort an array of boolean values, you can use a compare function that checks if each value is true or false. This function will sort the boolean values with false values first, followed by true values.

let bools = [false, true, false, true, true];
bools.sort((a, b) => a - b); // [false, false, true, true, true]

Sorting an Array of Mixed Data Types

To sort an array of mixed data types, you can use a compare function that checks the values of each item in the array. This function will sort the items based on their values.

let mixed = [1, 'apple', true, 42, 'orange'];
mixed.sort((a, b) => {
  if (a < b) return -1;
  if (a > b) return 1;
  return 0;
}); // ['apple', true, 1, 42, 'orange']

As you can see, the items in the mixed array have been sorted based on their values. Keep in mind that comparing different data types can sometimes result in unexpected behavior, so be careful when sorting arrays of mixed data types.

Sorting Arrays of Objects: Simple Cases

Sorting arrays of objects in JavaScript is a powerful feature that allows you to manipulate and organize data in a variety of ways. Let's take a look at some simple cases that demonstrate how sorting arrays of objects works.

Sorting by a Single Property

The most straightforward way to sort an array of objects is by a single property, such as the name of a person or the age of a user. In this case, we can use the sort() method combined with a compareFunction that compares two values and returns either a negative, zero, or positive number, depending on the comparison.

For example, let's say we have an array of objects representing users with their names and ages:

 const users = [
   { name: 'John Doe', age: 23 },
   { name: 'Jane Smith', age: 20 },
   { name: 'Bob Johnson', age: 35 },
 ];

To sort this array by age, we can use the following code:

 const sortedUsers = users.sort((a, b) => {
   if (a.age < b.age) return -1;
   if (a.age > b.age) return 1;
   return 0;
 });

This code will sort the users array by their age in ascending order.

Sorting by Multiple Properties

Sorting by multiple properties is a more complex task, but it can be achieved by creating a compareFunction that compares each property one by one until a difference is found. For example, if we have an array of objects representing people with their names, ages, and heights, we could sort them first by age and then by height:

 const people = [
   { name: 'John Doe', age: 23, height: 170 },
   { name: 'Jane Smith', age: 20, height: 165 },
   { name: 'Bob Johnson', age: 23, height: 175 },
   { name: 'Alice Brown', age: 20, height: 160 },
 ];

 const sortedPeople = people.sort((a, b) => {
   if (a.age < b.age) return -1;
   if (a.age > b.age) return 1;
   if (a.height < b.height) return -1;
   if (a.height > b.height) return 1;
   return 0;
 });

In this example, the people array is sorted first by age in ascending order, and then by height in ascending order for people with the same age.

In conclusion, sorting arrays of objects in JavaScript is a useful technique that can help you manage and organize data in a variety of ways. By understanding how to use the sort() method and the compareFunction, you can easily sort arrays by a single property or by multiple properties, depending on your needs.

Sorting Arrays of Objects: Advanced Cases

Sorting an array of objects in JavaScript is an essential skill for any developer. However, sorting is not always as straightforward as it seems. In some cases, you may need to sort an array of objects based on multiple criteria, or you may need to apply a custom sort function to handle complex sorting requirements. In this section, we will explore these advanced cases and provide code examples to help you master sorting arrays of objects in JavaScript.

Sorting by Multiple Criteria

In many cases, you may need to sort an array of objects based on multiple criteria. For example, you may need to sort a list of employees by their last name, and then by their age within each last name group. To achieve this, you can use the sort() method with a custom sorting function.

Here is an example of how to sort an array of objects by multiple criteria:

const employees = [
  {firstName: 'John', lastName: 'Doe', age: 25},
  {firstName: 'Jane', lastName: 'Doe', age: 30},
  {firstName: 'Tom', lastName: 'Smith', age: 25},
  {firstName: 'Mary', lastName: 'Jones', age: 35},
];

employees.sort((a, b) => {
  if (a.lastName === b.lastName) {
    return a.age - b.age; // sort by age within each lastName group
  } else {
    return a.lastName.localeCompare(b.lastName); // sort by lastName
  }
});

In this example, we first check if the last names of two objects are the same. If they are, we compare their ages. If their ages are different, we sort by age within each last name group. If the last names of two objects are different, we sort by last name using the localeCompare() method.

Custom Sort Functions

In some cases, you may need to apply a custom sort function to handle complex sorting requirements. For example, you may need to sort a list of products based on their popularity, sales, and price. To achieve this, you can use the sort() method with a custom sorting function.

Here is an example of how to sort an array of objects using a custom sort function:

const products = [
  {name: 'ProductA', popularity: 200, sales: 100, price: 20},
  {name: 'ProductB', popularity: 150, sales: 200, price: 30},
  {name: 'ProductC', popularity: 300, sales: 50, price: 25},
  {name: 'ProductD', popularity: 100, sales: 300, price: 15},
];

function customSort(a, b) {
  const popularityScoreA = a.popularity * 0.5 + a.sales * 0.3 + a.price * 0.2;
  const popularityScoreB = b.popularity * 0.5 + b.sales * 0.3 + b.price * 0.2;
  return popularityScoreB - popularityScoreA;
}

products.sort(customSort);

In this example, we define a custom sort function that calculates a popularity score for each object based on the popularity, sales, and price values. We then compare the popularity score of two objects to determine their order. Finally, we use the sort() method with the custom sort function to sort the array of objects.

Real Code Examples

To further illustrate how to sort an array of objects in JavaScript effectively, consider the following :

Example 1: Sorting an array of objects by property

Suppose you have an array of objects representing employees, and you want to sort the array based on their salaries in ascending order. Here's how you can accomplish this using the sort() method and arrow function syntax:

const employees = [
  { name: 'John', salary: 45000 },
  { name: 'Mary', salary: 60000 },
  { name: 'Peter', salary: 35000 },
  { name: 'Susan', salary: 55000 }
];

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

console.log(employees);

The output will be:

[
  { name: 'Peter', salary: 35000 },
  { name: 'John', salary: 45000 },
  { name: 'Susan', salary: 55000 },
  { name: 'Mary', salary: 60000 }
]

Example 2: Sorting an array of objects by multiple properties

Suppose you have an array of objects representing products, and you want to sort the array first by category in ascending order, then by price in descending order. Here's how you can accomplish this using the sort() method and arrow function syntax:

const products = [
  { name: 'Chair', category: 'Furniture', price: 150 },
  { name: 'Table', category: 'Furniture', price: 250 },
  { name: 'Bookshelf', category: 'Furniture', price: 100 },
  { name: 'Laptop', category: 'Electronics', price: 1000 },
  { name: 'Phone', category: 'Electronics', price: 800 }
];

products.sort((a, b) => {
  if (a.category === b.category) {
    return b.price - a.price;
  }
  return a.category.localeCompare(b.category);
});

console.log(products);

The output will be:

[
  { name: 'Bookshelf', category: 'Furniture', price: 100 },
  { name: 'Chair', category: 'Furniture', price: 150 },
  { name: 'Table', category: 'Furniture', price: 250 },
  { name: 'Laptop', category: 'Electronics', price: 1000 },
  { name: 'Phone', category: 'Electronics', price: 800 }
]

These should give you a better understanding of how to sort arrays of objects in JavaScript. Try experimenting with different properties and sorting orders to get a feel for how it works, and don't forget to use the sort() method in combination with arrow function syntax for concise and readable code.

Best Practices for Sorting Arrays of Objects

Sorting an array of objects in JavaScript can be a daunting task, especially if you are not familiar with the best practices for doing so. Here are some tips to help you sort your arrays efficiently and effectively:

  1. Use a comparison function: The sort() method in JavaScript accepts an optional comparison function. This function takes two parameters and returns a value less than zero if the first parameter is smaller, zero if they are equal, and a value greater than zero if the first parameter is larger. Using a comparison function ensures that the sort order is correctly maintained based on the values of the objects in the array.

  2. Use the stable comparison: A stable comparison ensures that the relative order of objects in the array is maintained even when two objects have the same value. This is essential for arrays where sorting does not just depend on values, but also on the original order of objects.

  3. Avoid unnecessary comparisons: When sorting large arrays, it is important to avoid unnecessary comparisons as they can cause a significant drop in performance. Ensure that the comparison function only compares the properties that affect the sorting order.

  4. Use the appropriate data type: Make sure the data type in the array is consistent. If it is not consistent, it can affect the accuracy of the comparison during the sort.

  5. Keep the original array intact: It is good practice to avoid modifying the original array to prevent unwanted side effects. Instead, you can create a copy of the original array and apply the sort operation on the copy.

By following these best practices, you can efficiently and accurately sort arrays of objects in JavaScript. Remember to always test your code rigorously to ensure that it produces accurate results.

Conclusion

:

Sorting an array of objects in JavaScript is an essential skill that every programmer should have. By mastering this skill, you can easily manipulate and organize data on your web applications.

In this tutorial, we have covered the basics of sorting an array of objects in JavaScript, as well as more advanced techniques such as sorting by multiple keys and using custom comparison functions. Additionally, we have provided real code examples to help you understand how these techniques can be implemented in practice.

Remember that sorting an array of objects in JavaScript can be a complex process, especially when dealing with large datasets. But with a solid understanding of the concepts and techniques covered in this tutorial, you can confidently tackle even the most challenging sorting tasks.

We hope that this tutorial has been helpful in expanding your knowledge of JavaScript programming. If you have any questions or feedback, please don't hesitate to reach out to us. Happy coding!

Cloud Computing and DevOps Engineering have always been my driving passions, energizing me with enthusiasm and a desire to stay at the forefront of technological innovation. I take great pleasure in innovating and devising workarounds for complex problems. Drawing on over 8 years of professional experience in the IT industry, with a focus on Cloud Computing and DevOps Engineering, I have a track record of success in designing and implementing complex infrastructure projects from diverse perspectives, and devising strategies that have significantly increased revenue. I am currently seeking a challenging position where I can leverage my competencies in a professional manner that maximizes productivity and exceeds expectations.
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