[{"name":"apple","total":20,"baskets":[{"name":"basket_green","total":0},{"name":"basket_blue","total":0},{"name":"basket_red","total":0}]}]

db.collection.update({},[{"$set":{"baskets":{"$map":{"input":"$baskets","as":"basket","in":{"$cond":{"if":{"$eq":["$$basket.name","basket_blue"]},"then":{"name":"$$basket.name","total":"$total"},"else":"$$basket"}}}}}}])