Simon says for d3 donut charts

d3-simon.js

(function() {
    var shuffle = function(items) {
        var newOrder = [];
        var usedNumbers = {};
        var i = 0;
        while (newOrder.length < items.length) {
            i++;
            var rando = Math.floor(Math.random() * items.length);
            if (!usedNumbers[rando.toString()]) {
                usedNumbers[rando.toString()] = true;
                newOrder.push(rando);
            }
        }
        return newOrder;
    };

    arcs = d3.selectAll('path');
    var clicks = [];

    arcs.on('click', function(d, i) {
        clicks.push(i);
    });

    newOrder = shuffle(arcs[0]);
    var count = 0;

    var interval = setInterval(function() {
        arc = d3.select(arcs[0][newOrder[count]]);

        arc.attr('fill', function(d, i) {
                d._fill = d.fill;
                return d3.interpolate(d.fill, 'white')(0.35);
            })
            .transition()
            .duration(300)
            .attr('fill', function(d, i) {
                d.fill = d._fill;
                return d.fill;
            });

        count++;
        if (count === newOrder.length) {
            clearInterval(interval);
        }
    }, 900);

    d3.select('text').on('click', function() {
        var score = 0;
        for (var i = 0; i < newOrder.length; i++) {
            if (newOrder[i] === clicks[i]) {
                score++;
            }
        }

        if (score === newOrder.length) {
            alert('Congrats you beat Simon');
        } else {
            alert('You lost to Simon!');
        }
        console.log(clicks, newOrder);
    });
})();