Database
[{"_id":{"$oid":"654e74b1325312179d479295"},"myid":"id123","array":[7,98,2,35,76]}]
Query
db.collection.aggregate([{"$set":{"array":{"$let":{"vars":{"measures":["val0","val1","val2","val3","val4"]},"in":{"$zip":{"inputs":["$$measures","$array"]}}}}}},{"$set":{"array":{"$map":{"input":"$array","as":"element","in":{"$arrayToObject":[[{"k":{"$first":"$$element"},"v":{"$last":"$$element"}}]]}}}}},{"$merge":{"into":"_id","on":"_id"}}])