[{_id:ObjectId("6222ca4252925ad4c3faec08"),value:["test1","test2"]}]

db.collection.aggregate([{"$project":{"provider":{"$arrayToObject":{"$map":{"input":"$value","as":"v","in":[{"$concat":["value",{"$toString":{"$indexOfArray":["$value","$$v"]}}]},"$$v"]}}}}}])