CODEWITHSUNDEEP
flutterdart
Burak Akyalçın
Burak Akyalçın

Reputation: 337

Dart - Cannot create toJSON method

I have a User object and I want to be able to decode it from JSON and convert it to a JSON as well. fromJSON() method works fine but when I try to add toJSON() method the compiler gets mad. Any idea on this?

Missing type arguments for map literal.  Try adding an explicit type, or remove implicit-dynamic from your analysis options file.

Here is my User model

class User {
  int id;
  String userName;

  User({this.id, this.userName});

  factory User.fromJson(dynamic json) {
    return User(
        id: int.parse(json['id'].toString()),
        userName: json['user_name'].toString());
  }

  Map<String, dynamic> toJson() =>
      {
        'id': id,
        'user_name': userName,
      };
}

Upvotes: 1

Views: 969

Answers (2)

Hanoch Liao
Hanoch Liao

Reputation: 1

remove analysis_options.yaml or enable implicit-dynamic.

Upvotes: 0

Kirill Bubochkin
Kirill Bubochkin

Reputation: 6353

As per error message, you have implicit-dynamic forbidden in your static analysis settings. You have 2 options:

  1. Check your analysis_options.yml file, look for implicit-dynamic: false line and delete it (or change to true).

  2. Add explicit type to the map in your code:

Map<String, dynamic> toJson() => <String, dynamic>{
      'id': id,
      'user_name': userName,
    };

I would go with the second way because implicit dynamics can lead to some subtle errors, and it's better to forbid them.

Upvotes: 2

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