If you ever need to randomly sort an array of items in JavaScript, here’s a simple function to help you do so:

var shuffleArray = function (array) {
    // Create a copy of the array so that we don't shuffle the original one
    var arrayCopy = array.slice(0);
    // Shuffle the array
    return arrayCopy.sort(function() {
        return Math.random() - 0.5
    })
}

To use it, pass in any array.

var characters = ['Voldemort', 'Harry', 'Snape', 'Hagrid'];
var shuffledCharacters = shuffleArray( characters );
// ex. return ["Harry", "Snape", "Hagrid", "Voldemort"]