RandomBooleanBalancer

gistfile1.js

// from http://sbcgamesdev.blogspot.gr/2017/01/phaser-tutorial-how-to-balance-random.html
// converted to JS
// all rights reserved to Tomáš Rychnovský

var RandomBooleanBalancer = function(balancer) {

    var _rnd = new Phaser.RandomDataGenerator([0,1]);
    var _lbound;
    var _ubound;
    var _currentBalance;

    // -------------------------------------------------------------------------
    // balancer - how many consecutive same values maximally
    function init(balancer) {
        reset(balancer);
    }

    // -------------------------------------------------------------------------
    function reset(balancer) {
        balancer -= 1;

        var lbound = Math.ceil(balancer / 2);
        _lbound = -lbound;
        _ubound = balancer - lbound;

        _currentBalance = balancer === 0 ? _rnd.integerInRange(-1, 0) : 0;
    }

    // -------------------------------------------------------------------------
    function getBoolean() {

        var result = _currentBalance + _rnd.integerInRange(_lbound, _ubound);

        _currentBalance += result >= 0 ? -1 : 1;

        return result >= 0;
    }

    init(balancer);

    return {
        reset: function(balancer) {
            reset(balancer);
        },
        getBoolean: function() {
            return getBoolean();
        }
    }
};