Ordering

DO

DO place “dart:” imports before other imports

import 'dart:async'; 
import 'dart:html'; 

import 'package:bar/bar.dart'; 
import 'package:foo/foo.dart';

DO place “package:” imports before relative imports

import 'package:bar/bar.dart'; 
import 'package:foo/foo.dart'; 

import 'util.dart';

DO specify exports in a separate section after all imports

import 'src/error.dart'; 
import 'src/foo_bar.dart'; 

export 'src/error.dart';

DO sort sections alphabetically

import 'package:bar/bar.dart'; 
import 'package:foo/foo.dart'; 

import 'foo.dart'; 
import 'foo/foo.dart';

PREFER

PREFER placing external “package:” imports before other imports

If you have a number of “package:” imports for your own package along with other external packages, place yours in a separate section after the external ones.

import 'package:bar/bar.dart'; 
import 'package:foo/foo.dart'; 

import 'package:my_package/util.dart';