How to convert list getting from future method to Map<String, dynamic>

Question

I want to convert the list coming from getPosts method (getting result from the web json and stored in the posts list) to List

Post Class

class Post {
  final int userId;
  final String id;
  final String title;
  final String body;

  Post(this.userId, this.id, this.title, this.body);
 
}

   Future<List<Post>> getPosts() async {
    var data = await http
        .get("https://jsonplaceholder.typicode.com/posts");
    var jasonData = json.decode(data.body);
    List<Post> posts = [];

    for (var i in jasonData) {
      Post post = Post(i["userId"], i["id"], i["title"], i["body"]);
      posts.add(post);
    }


    return posts;
  }

I tried to put the result directly to this method

  static List<Map> convertToMap({List myList }) {
    List<Map> steps = [];
    myList.forEach((var value) {
      Map step = value.toMap();
      steps.add(step);
    });
    return steps;
  }

but it's not working, I see this error

The argument type 'List<Map<dynamic, dynamic>>' can't be assigned to the parameter type 'Map<String, dynamic>'.

Solution

Change List<Map> by List<Map<String, dynamic>>

  static List<Map<String, dynamic>> convertToMap({List myList }) {
    List<Map<String, dynamic>> steps = [];
    myList.forEach((var value) {
      Map step = value.toMap();
      steps.add(step);
    });
    return steps;
  }

Comments

[lsaudon]

Why put it in a map list?

[Mahmoud Metawee]

@lsaudon I wanna store it to push it to firestore collection, it's need to be Map<String, dynamic>

[nvoigt]

Please post a minimal reproducible example.

[lsaudon]

I don't think you should do it by hand. Look pub.dev/packages/json_serializable

[lsaudon]

id is int not a String

[Mahmoud Metawee]

@lsaudon I tried your method but I think the issue is with Future, I see this The argument type 'Future<List<Post>>' can't be assigned to the parameter type 'List<dynamic>'.

[Mahmoud Metawee]

@lsaudon I'll try this library thank you

[nvoigt]

This is not a minimal reproducible example. You said you want to do X, yet in your code I see no attempt to do X. You have not even posted the lines where you do what you want to do. Where the error supposedly occurs. We cannot help you by speculating what code you may have written and then telling you what errors you may have made in that code we think you maybe wrote. Please post a fully working example that demonstrates the error you get.