Access Modifiers in Dart

Access Modifiers in Dart Overview

Dart controls visibility through a simple but powerful privacy model based on library boundaries. Unlike many OOP languages, Dart uses implicit public access and explicit private access (with _ prefix) to manage encapsulation and API boundaries.

Key Concepts

1. Public and Private Members

  • Default public visibility
  • _ prefix for private members
  • Applies to classes, variables, and functions

2. File-level Privacy

  • Privacy within the same library
  • Multiple files in the same library
  • Part-of directives

3. Cross-library Privacy

  • Private members in library exports
  • Hiding implementation details
  • Public-facing APIs

4. Best Practices

  • When to use private members
  • Library design principles
  • Documentation conventions
  • Testing private members