## How to sort an array of numbers in JavaScript?

October 29, 2020 - 3 min read

To sort an array of numbers in JavaScript, you can use the sort() method on the array object.

## Sort the array in ascending order

To sort the numbers array in ascending order, you have to pass a function to the sort() method to customize its behavior, and the function will be passed 2 elements a and b while iterating.

You have to subtract a-b and return the result.

// array of numbers
const numArr = [34, 56, 78, 90, 4, 5, 6, 34];

// sort array
// in ascending order
numArr.sort((a, b) => {
return a - b;
});

console.log(numArr); // [4, 5, 6, 34, 34, 56, 78, 90]

Here a is the second element of the current iteration and b is the first element of the current iteration.

If the result of the subtraction is a negative number, then the numbers are swapped and the array contains numbers in ascending order.

See this example live in JSBin.

## Sort the array in descending order

To sort the numbers array in ascending order, you have to pass a function to the sort() method to customize its behavior, and the function will be passed 2 elements a and b while iterating.

You have to subtract b-a and return the result.

// array of numbers
const numArr = [34, 56, 78, 90, 4, 5, 6, 34];

// sort array
// in descending order
numArr.sort((a, b) => {
return b - a;
});

console.log(numArr); // [90, 78, 56, 34, 34, 6, 5, 4]

Here a is the second element of the current iteration and b is the first element of the current iteration.

If the result of the subtraction is a negative number, then the numbers are swapped and the array contains numbers in descending order.

See this example live in JSBin.

### Some resources if you want to get more information on using various sorting algorithms in JavaScript:

• Bubble sort algorithm in JavaScript

• Insertion sort algorithm in JavaScript

• Selection sort in JavaScript

• Merge Sort in JavaScript