How to Sort Array in Descending Order in JavaScript

To sort an array in descending order in JavaScript, use the sort() method with a compare function that subtracts the first element from the second, like array.sort((a, b) => b - a). This tells JavaScript to order elements from largest to smallest.

Syntax

The sort() method sorts the elements of an array in place. To sort numbers in descending order, provide a compare function:

• array.sort((a, b) => b - a)

Here, a and b are two elements being compared. Subtracting b - a sorts from highest to lowest.

javascript

array.sort((a, b) => b - a);

Example

This example shows how to sort a list of numbers from largest to smallest using sort() with a compare function.

javascript

const numbers = [5, 2, 9, 1, 5, 6];
numbers.sort((a, b) => b - a);
console.log(numbers);

Output

[9, 6, 5, 5, 2, 1]

Common Pitfalls

Without a compare function, sort() converts elements to strings and sorts them alphabetically, which can give wrong results for numbers.

For example, [10, 2, 1].sort() results in [1, 10, 2], not numeric order.

Always provide a compare function for numeric sorting.

javascript

const arr = [10, 2, 1];
arr.sort();
console.log(arr); // Wrong: [1, 10, 2]

arr.sort((a, b) => b - a);
console.log(arr); // Correct: [10, 2, 1]

Output

[1, 10, 2]
[10, 2, 1]

Quick Reference

Method	Description	Example
sort()	Sorts array elements alphabetically by default	[3, 1, 2].sort() → [1, 2, 3] (as strings)
sort((a, b) => a - b)	Sorts numbers in ascending order	[3, 1, 2].sort((a,b) => a-b) → [1, 2, 3]
sort((a, b) => b - a)	Sorts numbers in descending order	[3, 1, 2].sort((a,b) => b-a) → [3, 2, 1]

Key Takeaways

Use array.sort((a, b) => b - a) to sort numbers in descending order.

Always provide a compare function when sorting numbers to avoid string-based sorting.

The sort() method changes the original array in place.

Without a compare function, sort() sorts elements as strings alphabetically.

Descending order means sorting from largest to smallest.