Reverse alphabetically sorted strings in JavaScript

We are required to write a JavaScript function that takes in a lowercase string and sorts it in the reverse alphabetical order i.e., 'z' should come before 'y', 'b' before 'a', and so on.

Example

If the input string is:

const str = "hello";

Then the output should be:

const output = "ollhe";

Using Custom Comparator Function

Here's how we can achieve reverse alphabetical sorting using a custom comparator:

const string = 'hello';
const sorter = (a, b) => {
    const legend = [-1, 0, 1];
    return legend[+(a  {
    const strArr = str.split("");
    return strArr
    .sort(sorter)
    .join("");
};
console.log(reverseSort(string));

ollhe

How It Works

The custom sorter function uses a clever approach:

• When a is true, it returns legend[1] which is 1
• When a is false, it returns legend[0] which is -1
• This effectively reverses the normal sorting order

Alternative Method: Simple Reverse Sort

A more straightforward approach using built-in reverse comparison:

const reverseAlphabetical = str => {
    return str.split("")
              .sort((a, b) => b.localeCompare(a))
              .join("");
};

console.log(reverseAlphabetical("hello"));
console.log(reverseAlphabetical("javascript"));

ollhe
vstricpaja

Comparison

Conclusion

Both methods effectively reverse alphabetical sorting. The localeCompare() approach is more readable, while the custom comparator offers slightly better performance for large strings.