http dart: How to send a Map in the query parameters of a request?

Question

I have a http request like this using the http package:

import 'package:http/http.dart' as http;

Uri url = Uri.http(
  'http://sample.com',
  '/request',
  {
    'dataMap': {
      'key1': ['item1', 'item2']
      'key2': ['item1', 'item2']
    },
  },
);

I get this error:

 _TypeError (type '_InternalLinkedHashMap<String, List<String>>' is not a subtype of type 'Iterable<dynamic>')

The error is not thrown if I don't put a map in the query parameters.

So how do I send a Map?

Answer 1

You could jsonEncode the map:

import 'dart:convert';

void main() {
  Uri url = Uri.http(
    'sample.com',
    '/request',
    {
      'dataMap': jsonEncode({
        'key1': ['item1', 'item2'],
        'key2': ['item1', 'item2']
      }),
    },
  );
  
  print(url);
}