How to sort and format last names in an array alphabetically in JavaScript

Question

I have an array moonwalkers and wrote a function alphabetizer to sort the names in alphabetical order and format them with last name first.

It works fine but how do I write better code?

I used this article by Hubrik and referred to Stack Overflow to understand how sort works in JS.

I tried to rework the compare function into the last name variable and made a mess of it. I suspect this is because I am still trying to get my head around scopes and hoisting.

var moonWalkers = [
  "Neil Armstrong",
  "Buzz Aldrin",
  "Pete Conrad",
  "Alan Bean",
  "Alan Shepard",
  "Edgar Mitchell",
  "David Scott",
  "James Irwin",
  "John Young",
  "Charles Duke",
  "Eugene Cernan",
  "Harrison Schmitt"
];


var finalNameList = [];

function alphabetizer(names) {
    
    // compare last names
    function compare (a, b) {
        var aName = a.split(" ");
        var bName = b.split(" ");
        var aLastName = aName[aName.length - 1];
        var bLastName = bName[bName.length - 1];
        
        if (aLastName < bLastName) return -1;
        if (aLastName > bLastName) return 1;
        return 0;
    }
    
    names.sort(compare);
    
    // to format names
    for (i = 0; i < names.length; i++) {
        var lastName = names[i].split(" ")[1];
        var firstName = names[i].split(" ")[0];
        var newName = lastName + ", " + firstName;
        
        //  push newName to global var finalNameList
        finalNameList.push(newName);
    }
    
    return finalNameList;
}

console.log(alphabetizer(moonWalkers));

The body of your sort callback could be shortened to `return a.split(" ")[1].localeCompare(b.split(" ")[1]);` - Or format the names *before* sorting and you can just `return finalNameList.sort();` — nnnnnn, Aug 20 '16 at 04:23

Mottie · Accepted Answer · 2016-08-20T12:50:54.637

That method isn't ideal because it is only comparing last names. People with the same last name won't get sorted by their first name.

Try this instead:

var moonWalkers = [
  "Neil Armstrong",
  "Buzz Aldrin",
  "Pete Conrad",
  "Alan Bean",
  "Alan Shepard",
  "Edgar Mitchell",
  "David Scott",
  "James Irwin",
  "John Young",
  "Charles Duke",
  "Eugene Cernan",
  "Harrison Schmitt"
];

function alphabetizer(names) {
    var list = [];

    // format names first
    for (i = 0; i < names.length; i++) {
        var lastName = names[i].split(" ")[1];
        var firstName = names[i].split(" ")[0];
        var newName = lastName + ", " + firstName;
        
        //  push newName to global var finalNameList
        list.push(newName);
    }

    // compare entire name
    return list.sort();
}

console.log(alphabetizer(moonWalkers));

Update: This version will include the middle, or nick names in the result. It won't work as expected if the name includes a suffix like "Jr" or "Esq".

var moonWalkers = [
  "Neil Armstrong",
  "Edwin \"Buzz\" Aldrin",
  "Charles \"Pete\" Conrad",
  "Alan Bean",
  "Alan Shepard",
  "Edgar Mitchell",
  "David Scott",
  "James Irwin",
  "John Young",
  "Charles Duke",
  "Eugene Cernan",
  "Harrison \"Jack\" Schmitt"
];

function alphabetizer(names) {
  return names.map(function(name) {
    var full = name.split(" "),
      last = full.pop();
    return last + ", " + full.join(" ");
  }).sort();
}

console.log(alphabetizer(moonWalkers));

@dho, Mottie, `function alphabetizer(names) { return names.map(function(name){ var [firstName, lastName] = name.split(" "); return lastName + ", " + firstName; }).sort(); }` — Thomas, Aug 20 '16 at 04:47
Thanks @Thomas, I've actually updated my answer to include more than just the first and last name. — Mottie, Aug 20 '16 at 12:51

How to sort and format last names in an array alphabetically in JavaScript

1 Answers1