Sort a string alphabetically using a function

Question

Imagine you were given a string and you had to sort that string alphabetically using a function. Example:

sortAlphabets( \'drpoklj\' ); //=> returns \'djklopr         


        

Answer 1

As previous answers have shown, you convert the string to an array of single-character strings, sort that, and then recombine it into a string. But, using split isn't the best practice way to do that first step, because a JavaScript string is a series of UTF-16 code units with invalid surrogate pairs tolerated, and split("") splits up surrogate pairs into their individual code units, potentially separating them, thus breaking the code point (loosely: character) they're supposed to form as a pair. So if you have an emoji in the string (for instance) or any of hundreds of thousands of characters in non-Western scripts, those can get broken.

In ES5 and earlier, correctly splitting the string required that you detect and handle surrogate pairs to ensure they stayed together, which was a bit of a pain and involved checking charCodeAt for specific ranges of values.

As of ES2015+, it's really easy: You just use the string's iterator, which is defined to provide each code point in the string, whether that's a single code unit or two. To get an array of the code points, you can use the iterator via spread notation ([...str]) or Array.from (Array.from(str)).

So using that, we get:

function sortAlphabets(str) {
    return [...str].sort((a, b) => a.localeCompare(b)).join("");
}

Live Example:

// Using the iterator
function sortAlphabets(str) {
    return [...str].sort((a, b) => a.localeCompare(b)).join("");
}

// Using split("")
function sortAlphabetsUsingSplit(str) {
    return str.split("").sort((a, b) => a.localeCompare(b)).join("");
}

const str = "

             

                                                        
            

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