sort Examples

The general syntax for this method is:

arrayName.sort()

This method arranges the elements of an array into increasing order. For strings, this means alphabetical order. HOWEVER, the results are not always what we expect.

Example

Alphabetical order?

let letters = ['f', 'c', 'B', 'X', 'a'];

letters.sort();
console.log(letters);

Output

[ 'B', 'X', 'a', 'c', 'f' ]

From the alphabet song, we know that 'a' comes before 'B' (and certainly before 'X'), but JavaScript treats capital and lowercase letters differently. The default sort order places capital letters before lowercase.

Example

let mixed = ['a', 'A', 20, 40];

mixed.sort();
console.log(mixed);

Output

[ 20, 40, 'A', 'a' ]

When numbers and strings are sorted, the default order places numbers before all letters.

Example

Numerical sorting.

let numbers = [2, 8, 10, 400, 30];

numbers.sort();
console.log(numbers);

Output

[ 10, 2, 30, 400, 8 ]

Here JavaScript gets truly bizarre. How is 8 larger than 400?

When JavaScript sorts, it converts all entries into strings by default. Just like 'Apple' comes before 'Pear' because 'A' comes before 'P', the string '400' begins with a '4', which comes before any string starting with an '8'. Looking only at the first digit in each number, we see the expected progression (1, 2, 3, 4, 8).

Later in this course, we will explore ways to fix this issue and correctly sort numerical arrays.