Dart experience - Http request, List manipulation, DOM manipulation

index.html

<div>Insert a String</div>
<input type="text" id="text-in"/>
<input type="button" value="ok" id="btn-in"/>
<div id="text-res">_______</div>

main.dart

import 'dart:html';
import 'dart:convert';

void main() {
  querySelector('#btn-in').onClick.listen((e) => get());
}

void get(){
 	HttpRequest.getString('https://swapi.co/api/people')
    .then((res) => filter(res));
}

void filter(String data){
  print((querySelector('#text-in') as InputElement).value);
                        
  List sData = json.decode(data)['results'];
  sData.retainWhere((el) => el['name'].toString().contains(
    (querySelector('#text-in') as InputElement).value));
  
  print(sData);
  
  querySelector('#text-res').text = '';
  
  sData.forEach((el) => 
                querySelector('#text-res').text = 
                querySelector('#text-res').text + ', ' + el['name']);
}