How to explode a camel cased string

ExplodingCamels

filters: {
        'explodingCamels': function(string) {
            var toReturn = '';
            for (var i = 0; i < string.length; i++) {
                var character = string.charAt(i);
                if (isNaN(character * 1)) {
                    if (i != 0 && character == character.toUpperCase()) {
                        toReturn += ' ';
                    }
                }
                toReturn += character;
            }
            return toReturn;
        }
    }