In typescript

//user is coming from firebase Users collection    
let userData = user.data() as {name:string, age:int}

What will be the alternatives of above code in dart?

CodePudding user response：

Json like data type in dart is Map but it's handy to code. The most efficient way is using Json Serialization.

Use a User model, and parse json to it,

User userData = User.fromJson(user.data());

You can generate Model class directly from Json automatically from here. So no pain in the neck.

User model class will be like this:

import 'dart:convert';

User userFromJson(String str) => User.fromJson(json.decode(str));

String userToJson(User data) => json.encode(data.toJson());

class User {
    User({
        this.name,
        this.age,
    });

    String name;
    int age;

    User copyWith({
        String name,
        int age,
    }) => 
        User(
            name: name ?? this.name,
            age: age ?? this.age,
        );

    factory User.fromJson(Map<String, dynamic> json) => User(
        name: json["name"],
        age: json["age"],
    );

    Map<String, dynamic> toJson() => {
        "name": name,
        "age": age,
    };
}

Happy coding TT

CodePudding user response：

This is how we can handle the data if it is coming from FireBase.

class MessageStreams extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
     return StreamBuilder<QuerySnapshot>(
       stream: _fireStore.collection('messages').snapshots(),
         builder: (context, snapshot) {
           if (!snapshot.hasData) {
             return Center(
               child: CircularProgressIndicator(
                 backgroundColor: Colors.lightBlue,
               ),
           );
        }
        final messages = snapshot.data.docs.reversed;
        List<MessageBubble> messageBubbles = [];
        for (var message in messages) {
          final messageText = message['text'];
          final messageSender = message['sender'];
          print(loggedInUser);
          print(loggedInUser.email);
          final currentUser = loggedInUser.email;
          if (currentUser == messageSender) {}
          final messageBubble = MessageBubble(
             messageSender, messageText, currentUser == messageSender);

          messageBubbles.add(messageBubble);
      }
      return Expanded(
        child: ListView(
          reverse: true,
          padding: EdgeInsets.symmetric(horizontal: 10.0, vertical: 20.0),
          children: messageBubbles,
        ),
      );
    },
  );
}

}