Question

function Player() {
  var score;

  this.getScore = function() { return score; }
  this.setScore = function(sc) { score = sc; }
}

function compare(playerA, playerB) {
  return playerA.getScore() - playerB.getScore();
}

var players = [];

players['player1'] = new Player();
players['player2'] = new Player();

Array(players).sort(compare);

I have code that is similar to the above. When I step through the code with a debugger, the compare function never gets called and the array isn’t sorted. I’m not sure what’s wrong with my code?

Answer 1

It’s not sorting because you have specified the keys that the variables within the array belong on. Sorting will only move the objects on integer-valued keys. You should see your sorting work if you create your array as follow:

var players = [new Player(), new Player()];

though, of course, it won’t be very effective since you have neither a score on which to sort or a method of identifying them. This’ll do it:

function Player(name, score) {
  this.getName = function() { return name; }
  this.getScore = function() { return score; }
  this.setScore = function(sc) { score = sc; }
}

function comparePlayers(playerA, playerB) {
  return playerA.getScore() - playerB.getScore();
}

var playerA = new Player('Paul', 10);
var playerB = new Player('Lucas', 5);
var playerC = new Player('William', 7);

var players = [playerA, playerB, playerC];

for (var i = 0; i < players.length; i++)
    alert(players[i].getName() + ' - ' + players[i].getScore());

players.sort(comparePlayers);

for (var i = 0; i < players.length; i++)
    alert(players[i].getName() + ' - ' + players[i].getScore());

Hope that helps.