find value in an array

var activityHistory = billingHistory.getBillingAccountDTOs()[1].getActivityItemDTOList();
// sort the array descending
var start = getTickCount();
arraySort(activityHistory,
	function (history1, history2){
		return compare(history1.getActivityEffectiveDate(), history2.getActivityEffectiveDate());
	}
);
//try to find a batch Number
var batchNumber = '';
for ( var history in activityHistory ) {
	if (history.getTransactionStatus() == 'RC') {
		batchNumber = history.getTransactionNumber();
		break;
	}
}