When to use part/part of versus import/export in Dart?

Question

I do not completely understand the difference between part/part of and import/export when using libraries in Dart. For e

Answer 1

Let's suppose we have a Dart library called mylib, whose file is lib/mylib.dart.

library mylib;

// Definitions

That library can be included in the main.dart file as

import 'package:mypackage/mylib.dart';

---

When you create a new library and use other libraries you want to make available automatically when using your package, then you use export:

library mylib;

export 'otherlib.dart';

// Definitions

You can use the show keyword to import/export only some parts of a library (like a class or something).

---

You are using the part of directive wrong here. You can't use both library and part of, which is used to specify the contents that belong to a library. For example, you can split your library file in more than one file (the parts):

Suppose we have in the file mylib.dart:

library mylib;

part 'src/class1.part';
// More parts

And then we have in another file src/class1.part the part specified in mylib.dart

part of mylib;

class Class1 { 
  /* ... */
}