Reorder an array in JavaScript

Reordering an array means changing the sequence of elements within the array. JavaScript provides several built-in methods to reorder arrays, each serving different purposes.

Using sort() for Alphabetical Ordering

The sort() method sorts array elements alphabetically in ascending order by default. It modifies the original array.

Original: Telangana,Uttar Pradesh,Karnataka,Kerala,TamilNadu
Sorted: Karnataka,Kerala,TamilNadu,Telangana,Uttar Pradesh

Using reverse() Method

The reverse() method reverses the order of elements in an array. The first element becomes the last, and the last becomes the first. This method modifies the original array.

Original: Vizag,Hyderabad,Bangalore,Gurgaon
Reversed: Gurgaon,Bangalore,Hyderabad,Vizag

Manual Swapping with Temporary Variable

You can manually reorder specific elements by swapping their positions using a temporary variable.

Original array: 23,53,12,87,9
After swapping: 53,23,87,12,9

The Problem with sort() for Numbers

The sort() method converts elements to strings before comparing, which causes incorrect sorting for numbers:

const numbers = [12, 34, 564, 1232134];
numbers.sort();
console.log(numbers);

[12, 1232134, 34, 564]

Using Compare Functions for Numeric Sorting

To properly sort numbers, use a compare function with sort(). The compare function returns:

• Negative value: first element comes before second
• Zero: no change in order
• Positive value: second element comes before first

Syntax

// Ascending order
array.sort(function(a, b) { return a - b; });

// Descending order
array.sort(function(a, b) { return b - a; });

Example

   
Click buttons to reorder the array:
   Ascending
   Descending
   

   

   

Ascending: 13,23,64,75,86
Descending: 86,75,64,23,13

Comparison of Methods

Conclusion

JavaScript offers multiple ways to reorder arrays: sort() for alphabetical ordering, reverse() for reversing, compare functions for numeric sorting, and manual swapping for custom arrangements. Choose the method based on your specific reordering needs.