Issues with flutter futures - map results in List<Future> - flutter

Question

I'm having issues with the return type of this HTTP request, I need to return Future<List> but the map is returning a List<Future>. I don't know how to get the CustomerInfo without it being a future and I don't know how to return it any other way.
if (response.statusCode == 200) {
Iterable l = json.decode(response.body);
final data = List.from(l.map((model) async {
final name = model['UserName'];
final id = model['UserICode'];
return {name, id};
}));
final users = data.map<CustomerInfo>((e) async {return await getFaxinfo(e.id, e.name);});
return users;
} else {
throw 'err';
}
}
Future<CustomerInfo> getFaxinfo(
String id,
String name,
) async {
final baseUrl = 'localhost';
final int port = 3003;
final accountsPath = '/accounts';
final accountsFaxInfoPath = '$accountsPath/fax-info';
final Map<String, dynamic> queryParam = {'id': id};
final uri = Uri(
scheme: 'http',
path: accountsFaxInfoPath,
host: baseUrl,
queryParameters: queryParam);
final response = await http.get(uri);
return CustomerInfo(sent: 200, received: 300, name: 'Test');
}

Answer 1

The problem is that an async function always returns a Future no matter if you call await inside it or not. To fix it a good approach is to use list comprehension. A simple for loop also would do.
Instead of those 2 maps that result in List<Future>:
final data = List.from(l.map((model) async {
final name = model['UserName'];
final id = model['UserICode'];
return {name, id};
}));
final users = data.map<CustomerInfo>((e) async {return await getFaxinfo(e.id, e.name);});
Do the following with list comprehension:
final users = [
for (final model in l)
await getFaxinfo(model['UserICode'], model['UserName'])
];
Now if you want to make the HTTP calls in parallel it's possible to do a Future.wait() in a List<Future> to get the result as List<CustomerInfo>. Something like the following:
final users = await Future.wait(l.map((model) async =>
await getFaxinfo(model['UserICode'], model['UserName'])));