load method Null safety

Future<String> load(
  1. String? apiKEY,
  2. Map data
)

Implementation

static Future<String> load(String? apiKEY,Map data) async{
  final doccument=parse(await rootBundle.loadString('$_PATH/main.html'));
  doccument.getElementsByTagName('head').first.append(doccument.createElement('script')..text=await rootBundle.loadString('$_JS_PATH/main.js'));
  final googleMapJs= doccument.createElement('script')..attributes['src']=
  apiKEY!=null?'https://maps.googleapis.com/maps/api/js?key=$apiKEY&callback=initMap'
      :'https://maps.googleapis.com/maps/api/js?sensor=false&callback=initMap';

  doccument.body!.append(googleMapJs);

  final mapData=doccument.getElementById('map-data');
  for (final el in data.entries){
    mapData!.attributes['data-${el.key}']=el.value.toString();
  }
  return doccument.outerHtml;
}