Understanding the JavaScript array.sort() Method

The array.sort() method is a built-in JavaScript method utilized to sort the elements of an array in place and returns the sorted array. The sorting is not numerical but lexicographical, that means it sorts numbers as strings.

Basic Usage of array.sort()

Let's take a quick example on how you can use the array.sort() method:

let array = [3, 1, 4, 1, 5, 9];
array.sort();
console.log(array); 
// Output: [1, 1, 3, 4, 5, 9]

In this example, the method array.sort() is called on the array. The sorted array is then logged to the console.

Working with String Arrays

When working with arrays of strings, the array.sort() method sorts elements as strings in lexicographic (or "dictionary") order:

let array = ['cat', 'Dog', 'bird', 'elephant'];
array.sort();
console.log(array); 
// Output: ["Dog", "bird", "cat", "elephant"]

Note that the sort is case-sensitive resulting in a sorted array with capital letter 'D' from 'Dog' appearing before lower case 'b' from 'bird'.

Sorting Numbers Correctly

To sort numbers in an ascending order, you need to pass a comparison function to the array.sort() method:

let array = [40, 1, 10, 200, 21];
array.sort(function(a, b){return a - b});
console.log(array);
// Output: [1, 10, 21, 40, 200]

In this instance, the comparison function is used to correctly sort the numbers in ascending order.

Best Practices

While array.sort() is a powerful tool, there are a few best practices to keep in mind:

• Always remember that it sorts in place, meaning it mutates the original array. This can be a problem if you want to keep the original array unsorted. In such case, make a copy of the array and then sort.
• Ensure that you are aware of lexicographic ordering when sorting numbers. If numerical order is needed, make sure to use a comparison function.
• When dealing with strings, it's case-sensitive. If you want case-insensitive sorting, you may need to use a custom comparison function.

In conclusion, the JavaScript array.sort() method is a versatile tool to sort both number and string arrays, when used correctly and with an understanding of its lexicographic sorting rules.