Rinse broccoli slaw mix with cold water; drain well.
Stir together mayonnaise, sugar, and vinegar in a large bowl; add slaw, onion, and dried cranberries, tossing gently to coat. Cover and chill 8 hours. Sprinkle with bacon and, if desired, pecans just before serving.
Note: For testing purposes only, we used Craisins for sweetened dried cranberries.