data_class_plugin 0.0.5

A tool that uses Dart's Analyzer to generate code on-the-fly.

Data Class Plugin

Data Class Plugin is a tool that uses the Dart Analysis Server to generate code on-the-fly.

This package is experimental and still under development, thus do not use it for applications in production.

---

Table of contents

• How it works
• Installation
• Generate the code you want
  • DataClass Annotation
  • Union Annotation
  • Enum Annotation
  • Enums
• Configuration
  • Configuration file
  • Available options
  • Configuration examples
• Notes
• Examples
• Development
• Known Issues

---

How it works

Data Class Plugin uses the analyzer system and analyzer plugin to get access on the source code, parse it and provide actions based on that.

Installation

1. In your project's pubspec.yaml add on dependencies the following

   dependencies:
     data_class_plugin: ^0.0.1
   

2. Update your analysis_options.yaml (in case you don't have it, just create a new one)

   Minimal analysis_options.yaml

   include: package:lints/recommended.yaml
   
   # You need to register the plugin under analyzer > plugins
   analyzer:
     plugins:
       - data_class_plugin
   

3. Restart the analysis server

   VSCode

   1. Open the Command Palette
      1. Windows/Linux: Ctrl + Shift + P
      2. MacOS: ⌘ + Shift + P
   2. Type and select "Dart: Restart Analysis Server"

   IntelliJ

   1. Open Find Action
      1. Windows/Linux: Ctrl + Shift + A
      2. MacOS: ⌘ + Shift + A
   2. Type and select "Restart Dart Analysis Server"

Generate the code you want!

DataClass Annotation

1. Create a simple class, annotate it with @DataClass() and provide final public fields for your model.

   @DataClass()
   class User {
      final String id;
      final String username;
   }
   

2. Place the cursor anywhere inside the User class

3. Run code actions on your IDE

   VSCode

   1. Windows/Linux: Ctrl + .
   2. MacOS: ⌘ + .

   Intellij

   1. Windows/Linux: Alt + Enter
   2. MacOS: ⌘ + Enter

4. Select Generate data class

Available methods are:

1. copyWith

   Generates a new instance of the class with optionally provide new fields values.

   If no value is provided (default), then true is assumed.

   MyClass copyWith(...) { ... }
   

2. hashAndEquals

   Implements hashCode and equals methods.

   If no value is provided (default), then true is assumed.

   @override
   bool operator ==(Object other) { ... }
   
   @override
   int get hashCode { ... }
   

3. $toString

   Implements toString method.

   If no value is provided (default), then true is assumed.

   @override
   String toString() { ... }
   

4. fromJson

   Generates a factory constructor that creates a new instance from a Map.

   If no value is provided (default), then false is assumed.

   factory MyClass.fromJson(Map<dynamic, dynamic> json) { ... }
   

5. toJson

   Generates a function that coverts this instance to a Map.

   If no value is provided (default), then false is assumed.

   Map<String, dynamic> toJson() { ... }
   

This configuration can be overriden in data_class_plugin_options.yaml, see Configuration.

Union Annotation

Adding this annotation to a class enables it to create union types.

Available union annotation toggles are:

1. dataClass

   Toggles code generation for toString, copyWith, equals and hashCode.

   If no value is provided (default), then true is assumed.

2. toJson

   Toggles code generation for fromJson.

   If no value is provided (default), then true is assumed.

3. fromJson

   Toggles code generation for toJson.

   If no value is provided (default), then true is assumed.

Enum Annotation

1. Create an enumeration with the last field closed by semicolon and annotate it with the @Enum() annotation.

   @Enum()
   enum Category {
      science,
      sports;
   }
   

2. Place the cursor anywhere inside the Category enum

3. Run code actions on your IDE

   VSCode

   1. Windows/Linux: Ctrl + .
   2. MacOS: ⌘ + .

   Intellij

   1. Windows/Linux: Alt + Enter
   2. MacOS: ⌘ + Enter

4. Select Generate enum

Available methods are:

1. $toString

   Implements toString method.

   If no value is provided (default), then true is assumed.

   @override
   String toString() { ... }
   

2. fromJson

   Generates a factory constructor that creates a new instance from a Map.

   If no value is provided (default), then false is assumed.

   factory MyClass.fromJson(Map<dynamic, dynamic> json) { ... }
   

3. toJson

   Generates a function that coverts this instance to a Map.

   If no value is provided (default), then false is assumed.

   Map<String, dynamic> toJson() { ... }
   

This configuration can be overriden in data_class_plugin_options.yaml, see Configuration.

Enums

Even if you don't use the @Enum() annotation, you can still generate methods in enums.

1. Create an enumeration with the last field closed by semicolon

   enum Category {
      science,
      sports;
   }
   

2. Place the cursor anywhere inside the Category enum

3. Run code actions on your IDE

   VSCode

   1. Windows/Linux: Ctrl + .
   2. MacOS: ⌘ + .

   Intellij

   1. Windows/Linux: Alt + Enter
   2. MacOS: ⌘ + Enter

4. A list with the following actions will be displayed

   1. Generate constructor
   2. Generate 'fromJson'
   3. Generate 'toJson'
   4. Generate 'toString'

Enums can have an optional single field of primary type to be used in the fromJson or toJson transforms, if not provided then the .name is used as the default json value.

enum Category {
   science(0),
   sports(1);

   final int value;
}

Configuration

You can customize the generated code produced by Data Class Plugin.

Configuration file

To create a custom configuration you need to add a file named data_class_plugin_options.yaml in the root folder of your project.

Available options

1. json

   Set the default naming convention for json keys.

   You can also override the default naming convention for the specified directories.

   Supported naming conventions: camelCase, snake_case, kebab-case & PascalCase.

2. data_class

   Set the default values for the provided methods of the @DataClass annotation, by specifying the directories where they will be enabled or disabled.

3. enum

   Set the default values for the provided methods of the @Enum annotation, by specifying the directories where they will be enabled or disabled.

Configuration examples

json:
  # Default naming convention for json keys
  key_name_convention: camel_case (default) | snake_case | kebab_case | pascal_case

  # Maps naming conventions to globs
  # You can provide a map of all the conventions you need and then a list with all the globs
  # key_name_conventions glob match takes precedence over key_name_convention
  key_name_conventions:
    <camel_case | snake_case | kebab_case | pascal_case>:
      - "a/glob/here"
      - "another/glob/here"

data_class:
  options_config:
    # For each of the provided methods you can provide a configuration
    # The configuration can be an enabled or disabled field that contains a list of globs
    # Default values for each options
    # copy_with, hash_and_equals, to_string (true), from_json, to_json (false)
    <copy_with | hash_and_equals | to_string | from_json | to_json>:
      default: boolean
      enabled:
        - "a/glob/here"
        - "another/glob/here"
      disabled:
        - "a/glob/here"
        - "another/glob/here"

union:
  options_config:
    # For each of the provided methods you can provide a configuration
    # The configuration can be an enabled or disabled field that contains a list of globs
    # Default values for each options
    # data_class (true), from_json(false), to_json (false)
    <data_class | from_json | to_json>:
      default: boolean
      enabled:
        - "a/glob/here"
        - "another/glob/here"
      disabled:
        - "a/glob/here"
        - "another/glob/here"

enum:
  options_config:
    # For each of the provided methods you can provide a configuration
    # The configuration can be an enabled or disabled field that contains a list of globs
    # Default values for each options
    # to_string (false), from_json(false), to_json (false)
    <to_string | from_json | to_json>:
      default: boolean
      enabled:
        - "a/glob/here"
        - "another/glob/here"
      disabled:
        - "a/glob/here"
        - "another/glob/here"

Notes

If the generated method doesn't exist it will be placed in the end of the class/enum body (before }), otherwise it will be re-generated to be up-to-date with current snapshot of the code (fields, annotations configuration).

The constructor is always generated at the start of the body (after {) for classes.

class MyClass {
  // constructor will be generated here
  
  final int a;
}

The constructor is always generated after the semicolon (;) in the values declaration for enums.

enum MyEnum {
  a,
  b,
  c;
  
  // constructor will be generated here
}

Examples

You can find a variety of examples in the Example folder and the source code from the Live Demo, as it was presented in the Flutter Greek Community, here.

Development

In order to see your changes in the plugin you need to modify tools/analyzer_plugin/pubspec.yaml and add the following section:

dependency_overrides:
  data_class_plugin:
    path: /absolute/path/to/root_project

And restart the analysis server (in case that fails run pub_get.sh).

Known Issues

1. When using IntelliJ/Android Studio the $toString parameter of the @DataClass annotation is not visible in the Suggestions list. However, you can still use it by typing it.