JavaScript Array sort()

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Examples

Sort array:

const fruits = ["Banana", "Orange", "Apple", "Mango"];
fruits.sort();

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Sort and then reverse the order:

const fruits = ["Banana", "Orange", "Apple", "Mango"];
fruits.sort();
fruits.reverse();

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Definition and Usage

The sort() sorts the elements of an array.

The sort() overwrites the original array.

The sort() sorts the elements as strings in alphabetical and ascending order.

Sort Compare Function

Sorting alphabetically works well for strings ("Apple" comes before "Banana").

But, sorting numbers can produce incorrect results.

"25" is bigger than "100", because "2" is bigger than "1".

You can fix this by providing a "compare function" (See examples below).

Syntax

array.sort(compareFunction)

Parameters

Parameter

Description

compareFunction

Optional.
A function that defines a sort order. The function should return a negative, zero, or positive value, depending on the arguments:

function(a, b){return a-b}

When sort() compares two values, it sends the values to the compare function, and sorts the values according to the returned (negative, zero, positive) value.

Example:

The sort function will sort 40 as a value lower than 100.

When comparing 40 and 100, sort() calls the function(40,100).

The function calculates 40-100, and returns -60 (a negative value).

Return Value

The array with the items sorted.

More Examples

Sort numbers in ascending order:

const points = [40, 100, 1, 5, 25, 10];
points.sort(function(a, b){return a-b});

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Sort numbers in descending order:

const points = [40, 100, 1, 5, 25, 10];
points.sort(function(a, b){return b-a});

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Find the lowest value:

const points = [40, 100, 1, 5, 25, 10];

// Sort the numbers in ascending order
points.sort(function(a, b){return a-b});

let lowest = points[0];

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Find the highest value:

const points = [40, 100, 1, 5, 25, 10];

// Sort the numbers in descending order:
points.sort(function(a, b){return b-a});

let highest = points[0];

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Find the highest value:

const points = [40, 100, 1, 5, 25, 10];

// Sort the numbers in ascending order:
points.sort(function(a, b){return a-b});

let highest = points[points.length-1];