Can we use json_serializable package to serialize and deserialize user models? - flutter

Question

After generating part 'UserModel.g.dart'; successfully, I got the following error upon trying to do
if (user != null) {
var uid = user.providerData.first.uid;
var displayName = user.providerData.first.displayName;
var email = user.providerData.first.email;
var phoneNumber = user.providerData.first.phoneNumber;
var providerId = user.providerData.first.providerId;
var photoUrl = user.providerData.first.photoURL;
UserModel userModel = UserModel(phoneNumber,
uid: uid,
displayName: displayName,
email: email,
providerId: providerId,
photoUrl: photoUrl);
Query query = users.where('uid', isEqualTo: uid);
query.get().then((querySnapshot) => {
if (querySnapshot.size < 1) {addUser(userModel)}
});
}
}
And here is my UserModel.dart without any errors in the file.
import 'package:json_annotation/json_annotation.dart';
part 'UserModel.g.dart';
#JsonSerializable()
class UserModel {
late String? uid;
late String? displayName;
late String? email;
late String? phoneNumber;
late String providerId;
late String? photoUrl;
UserModel(this.phoneNumber, {required this.uid, required this.displayName, required this.email,
required this.providerId, required this.photoUrl});
factory UserModel.fromJson(Map<String, dynamic> json) => _$UserModelFromJson(json);
Map<String, dynamic> toJson() => _$UserModelToJson(this);
}
Offcourse, I could manually map each value. But as recommended here https://flutter.dev/docs/development/data-and-backend/json, to prevent
Manual decoding does not perform well when your project becomes bigger. Writing decoding logic by hand can become hard to manage and error-prone. If you have a typo when accessing a nonexistent JSON field, your code throws an error during runtime.
I used the plugin json_serializable to sort of automate it.
But I got the following error:
Expected a value of type 'Map<String, dynamic>', but got one of type 'UserModel$'
Is this error expected due to incompatibility or am I doing something wrong? Please respond. Thank you very much. :)

Answer 1

I'm guessing this is where your issue is.
query.get().then((querySnapshot) => {
if (querySnapshot.size < 1) {addUser(userModel)}
});
Use the toJson method you created in your model class to pass in a Map instead of your custom UserModel object.
{addUser(userModel.toJson())}