How to Sort Array of Strings in JavaScript Easily

To sort an array of strings in JavaScript, use the array.sort() method. This method sorts the strings in place in ascending order by default, based on Unicode code points.

Syntax

The basic syntax to sort an array of strings is:

array.sort([compareFunction])

Here:

• array is your array of strings.
• sort() changes the array order.
• compareFunction is optional and lets you customize sorting rules.

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array.sort()

Example

This example shows how to sort an array of strings alphabetically using sort(). It also shows sorting with case-insensitive comparison using a compareFunction.

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const fruits = ['banana', 'Apple', 'cherry', 'apple'];

// Default sort (case-sensitive)
fruits.sort();
console.log('Default sort:', fruits);

// Case-insensitive sort
fruits.sort((a, b) => a.toLowerCase().localeCompare(b.toLowerCase()));
console.log('Case-insensitive sort:', fruits);

Output

Default sort: [ 'Apple', 'apple', 'banana', 'cherry' ]
Case-insensitive sort: [ 'apple', 'Apple', 'banana', 'cherry' ]

Common Pitfalls

By default, sort() compares strings based on Unicode values, which can lead to unexpected order especially with uppercase and lowercase letters.

Also, sorting numbers as strings can cause wrong order (e.g., '10' comes before '2').

To fix this, use a compareFunction like localeCompare() for strings or a numeric comparison for numbers.

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const names = ['bob', 'Alice', 'alice', 'Bob'];

// Wrong: default sort is case-sensitive
names.sort();
console.log('Wrong sort:', names);

// Right: case-insensitive sort
names.sort((a, b) => a.toLowerCase().localeCompare(b.toLowerCase()));
console.log('Right sort:', names);

Output

Wrong sort: [ 'Alice', 'Bob', 'alice', 'bob' ]
Right sort: [ 'alice', 'Alice', 'bob', 'Bob' ]

Quick Reference

• array.sort(): Sorts array elements as strings in ascending Unicode order.
• compareFunction: Optional function to define custom sort order.
• localeCompare(): Useful for case-insensitive or locale-aware string sorting.

Key Takeaways

Use array.sort() to sort strings alphabetically in JavaScript.

Default sort is case-sensitive and based on Unicode values.

Use a compareFunction with localeCompare() for case-insensitive sorting.

Always test sorting when strings have mixed cases or special characters.

Sorting modifies the original array in place.