fassets 0.0.1

Generate type-safe Dart constants from Flutter asset directories.

fassets

Generate type-safe Dart constants from your Flutter asset directories.

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Stop using magic strings like 'assets/icons/home.svg' — let fassets generate clean, static-const references for every asset in your project.

Features

• Reads declared asset paths from pubspec.yaml
• Generates one Dart class per asset folder with static const String entries
• Respects folder hierarchy — assets/icons/home/dark/ → AppDarkHomeIcons
• Incremental — only appends new constants, never removes or reorders
• Barrel file — auto-generates index.dart with sorted exports
• Selective — use --folder to regenerate a single subtree
• Zero external runtime dependencies in your Flutter project

Installation

dart pub global activate fassets

After activation, the fassets command is available globally from any directory.

Quick start

# cd into your Flutter project root
cd my_flutter_app

# Generate constants for all declared asset paths
fassets

# That's it! Import and use:

import 'package:my_flutter_app/src/core/domain/constants/assets/index.dart';

Image.asset(AppIcons.home);       // 'assets/icons/home.svg'
Image.asset(AppPng.splashBg);     // 'assets/png/splash_bg.png'

Usage

Run fassets from the root of your Flutter project (where pubspec.yaml lives):

# Generate for all declared asset paths
fassets

# Generate for a specific folder only
fassets -f assets/icons

# Custom output directory
fassets -o lib/constants/assets

# Verbose output
fassets -v

CLI options

Flag	Description
-h, --help	Print usage information
--version	Print the tool version
-v, --verbose	Show detailed output
-f, --folder	Process only this asset folder (full path from root)
-o, --output	Output directory (default: lib/src/core/domain/constants/assets)

How it works

1. Reads the flutter → assets section from your pubspec.yaml
2. Scans those directories recursively for files
3. Generates one Dart class per folder with static const String entries
4. Creates or updates a barrel index.dart that exports everything

Naming conventions

Input	Output
Folder assets/icons/	Class AppIcons
Folder assets/icons/home/	Class AppHomeIcons
Folder assets/icons/home/dark/	Class AppDarkHomeIcons
File home.svg	Constant home
File splash_bg.png	Constant splashBg
File delete_icon.svg	Constant deleteIcon

Regeneration behaviour

Scenario	Behaviour
File doesn't exist	Create fresh
File exists, no new assets	Touch nothing
File exists, new assets added	Append only new constants, leave rest untouched
Barrel index.dart	Only add new exports, never duplicate

--folder rules

• Must be the full path from project root, e.g. assets/icons/home
• Validated against pubspec.yaml — if not declared, warns and skips
• Only touches files belonging to that folder and its subfolders
• All other existing generated files are completely untouched

Edge cases

Situation	Behaviour
Folder in pubspec but missing on disk	Warn and skip
Folder exists but is empty	Warn and skip
--folder path not in pubspec	Warn and skip

Output structure

lib/src/core/domain/constants/assets/
├── app_icons.dart
├── app_png.dart
├── app_home_icons.dart
├── app_dark_home_icons.dart
└── index.dart              ← barrel file, always up to date

Example

The example/ directory contains a minimal Flutter project structure you can try:

example/
├── pubspec.yaml
├── assets/
│   ├── icons/
│   │   ├── home.svg
│   │   └── settings.svg
│   └── png/
│       └── splash_bg.png

Run from the example directory:

cd example
dart run ../bin/fassets.dart

Generated output:

app_icons.dart

// GENERATED BY fassets — DO NOT EDIT BY HAND
// ignore_for_file: constant_identifier_names

class AppIcons {
  AppIcons._();
  static const String baseUrl = 'assets/icons';

  static const String home = '$baseUrl/home.svg';
  static const String settings = '$baseUrl/settings.svg';
}

app_png.dart

// GENERATED BY fassets — DO NOT EDIT BY HAND
// ignore_for_file: constant_identifier_names

class AppPng {
  AppPng._();
  static const String baseUrl = 'assets/png';

  static const String splashBg = '$baseUrl/splash_bg.png';
}

index.dart

// GENERATED BY fassets — DO NOT EDIT BY HAND

export 'app_icons.dart';
export 'app_png.dart';

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Contributing

Contributions are welcome! Feel free to open issues and pull requests.

License

MIT