In this example below which unmaps the json from Firebase. Everywhere where I get data as Map<String, dynamic> - like orderId - its ok. But everywhere where I have map inside another map - like address - it gives me a warning

"Avoid method calls or property accesses on a "dynamic" target."

Its not critical but I found on google that it provokes productivity penalties. Can someone share why it is so and how to avoid it

Order.fromMap(Map<String, dynamic> data) {
    orderId = data['orderId'] as int;
    address = data['location']['address'].toString();

Solution 1: h8moss

First of all, I think it is worth noting that the mentioned size and runtime penalties are generally not a concern, they are likely to be unnoticable.

the best fix you have for this is simply to explicitly cast your value:

address = (data['location'] as Map<String, dynamic>)['address'].toString();

I am not sure if the above will be enough or if you will have to also cast address:

address = ((data['location'] as Map<String, dynamic>)['address'] as Object).toString()

The performance/size issue comes from the time it takes the application to figure out if data['location'] is a map. by adding as, you are telling it to not check and to not worry.