Javascript Array Sort Example | JS Array sort() Method

Javascript Array sort() is an inbuilt method that sorts all the elements of the array in place and returns that array. Javascript array sort() method can also accept the parameter like function. So it will sort an array based on that function logic. The default sort order is built on converting the item into strings and then comparing their sequences of UTF-16 code unit values.

Javascript Array Sort Example

The sort order can be either alphabetic or the numeric, and either the ascending (up) or descending (down). Javascript array sort() method is not a pure function because the sort() method changes the original array.

See the following syntax.

array.sort(compareFunction)

The compareFunction() parameter is an optional argument. The function that defines an alternative sort order and it should return a negative, zero, or positive value, depending on the arguments.

Let us take a simple example without a compare function. Create an app.js file and add the code.

// app.js

let points = [4, 10, 100, 25, 2, 20];
points.sort();

console.log(points);

Run the file by typing the node app in the terminal. See the output, and it is not what you have expected.

Output

Again, it does not merely put the values in ascending order. By default, the sort() method sorts the values as strings in alphabetical and ascending order.

Advance array sort() method example

Let us pass the compareFunction and change the default sort order.

// app.js

let points = [4, 10, 100, 25, 2, 20];
const sortAsc = (a, b) => a - b;
points.sort(sortAsc);

console.log(points);

So, here we are sorting the values in Ascending order, and we have written one JS function to do that. Run the file.

Output

We can do the Descending order also.

// app.js

let points = [4, 10, 100, 25, 2, 20];
const sortAsc = (a, b) => b - a;
points.sort(sortAsc);

console.log(points);

If the compareFunction() is not supplied, all non-undefined array elements are sorted by converting them to strings and comparing strings in UTF-16 code units order.

// app.js

let freelance = ['Upwork', 'Freelancer', 'Truelancer', 'PeoplePerHour'];
freelance.sort();

console.log(freelance);

Output

Sorting an array of objects

See the following example.

let apps = [
  { name: 'Amazon', value: 1 },
  { name: 'Amazon Prime', value: 21 },
  { name: 'Amazon Music', value: 10 },
  { name: 'Amazon Go', value: 100 },
  { name: 'Amazon Alexa', value: 13 }
];
apps.sort((a, b) => a.value-b.value);

console.log(apps);

Here, we have used the arrow function. Now, it will sort the Ascending order based on the values.

Output

Sorting non-ASCII characters and localeCompare()

For sorting strings with the non-ASCII characters, i.e., strings with accented characters like these (e, é, è, a, ä, etc.),

The strings from other languages apart from English: use the String.localCompare() method. The String.localCompare() function can compare those characters, so they appear in the right order.

// app.js

let words = ['réservé', 'premier', 'cliché', 'communiqué', 'café', 'adieu'];
words.sort(function (a, b) {
  return a.localeCompare(b);
});

console.log(words);

Finally, Javascript Array Sort Example Tutorial is over.