[{"categories":[{"entity_def_id":"category","permalink":"agriculture","uuid":"6a733ac8-b79c-e2d2-55b9-cc3d66435eb6","value":"Agriculture"},{"entity_def_id":"category","permalink":"food-and-beverage","uuid":"14364faa-63f9-0d45-7b6a-7378113364a2","value":"Food and Beverage"}]}]

db.collection.aggregate([{"$match":{}},{"$set":{"categories":{"$map":{"input":"$categories","as":"item","in":[{k:"$$item.entity_def_id",v:"$$item.value"}]}}}},{"$set":{"categories":{"$map":{"input":"$categories","as":"item","in":{"$arrayToObject":"$$item"}}}}}])