How to add a list to a Map<DateTime, List<dynamic>> dynamically

0
votes

I'm getting my documents from firebase keeping in a List. Currently I have this content in the list:

[{date: 02/02/2019, name: John}, {date: 03/03/2020, name: Louise}]

Then, in the following method, I transform this list to put in a map with my desired formatation.

Map formatMap(list){
    if(list.length > 1){
      for(int i = 0; i < list.length; i ++){
        dateFormatted = _formatDate(list[i]['date']);
        print(dateFormatted);
        if(i == 0){
          myMap[dateFormatted] = [];
        }
        myMap[dateFormatted].add({'date': list[i]['date'], 'name': events[i]['name']});
      }
    }else{
      dateFormatted = _formatDate(list['date']);
      myMap[dateFormatted] = [{'date': list['date'], 'name': list['name']}];
    }
    return myMap;
  }

I'm doing it because my expected result is:

{2020-12-31 12:00:00.000Z: [{date: 02/02/2019, name: John}, {date: 03/03/2020, name: Louise}]}

But running that method the return is:

[ERROR:flutter/lib/ui/ui_dart_state.cc(177)] Unhandled Exception: NoSuchMethodError: The method '[]=' was called on null. E/flutter (17862): Receiver: null E/flutter (17862): Tried calling: []=(Instance of 'DateTime', Instance(length:0) of '_GrowableList')

What I'm doing wrong? How can I perform to achieve my expected result?

1
listfirebaseflutterdart

1 Answers

0
votes

I guess you forgot to initialize the map:

myMap = {};