jolt_lint 2.0.0-beta.2

Lint tool for the Jolt reactive state management ecosystem, providing code quality checks and developer assistance.

Jolt Lint

A lint tool designed for the Jolt reactive state management ecosystem, providing code transformation assists and rule checks.

Installation

Add to analysis_options.yaml:

plugins:
  jolt_lint: ^2.0.0-beta.1

Requirements

⚠️ Version Requirement: This lint tool only supports Jolt version 2.0 and above.

Features

🔄 Code Transformation Assists

Convert to Signal

Quickly convert a regular variable to a Signal. This feature will:

• Wrap the variable type as Signal<T>
• Wrap the initialization expression as Signal(...)
• Automatically add .value access to all references within the variable's scope

Use case: When you want to convert a regular variable to a reactive signal.

Example:

// Before
int count = 0;

// After
Signal<int> count = Signal(0);
// All references to count are automatically changed to count.value

Convert from Signal

Convert a Signal back to a regular variable. This feature will:

• Unwrap the Signal<T> type to T
• Unwrap the Signal(...) initialization expression to the original value
• Automatically remove all .value access within the variable's scope

Use case: When you find that a variable doesn't need reactivity and want to simplify your code.

Example:

// Before
Signal<int> count = Signal(0);
print(count.value);

// After
int count = 0;
print(count);

📦 Widget Wrapping Assists

Multiple quick-assist features to wrap widgets, helping you rapidly integrate Jolt's reactive components.

Wrap with JoltBuilder

Wrap a widget with JoltBuilder to automatically react to changes in all accessed signals.

Use case: When you need a widget to react to signal changes.

Example:

// Before
Text('Hello')

// After
JoltBuilder(builder: (context) => Text('Hello'))

Wrap with JoltProvider

Wrap a widget with JoltProvider to provide reactive state in the widget tree.

Use case: When you need to provide shared reactive state in the widget tree.

Example:

// Before
MyWidget()

// After
JoltProvider(
  create: (context) => null,  // Fill in the actual creation logic
  builder: (context, provider) => MyWidget()
)

Wrap with JoltSelector

Wrap a widget with JoltSelector to achieve fine-grained state selection updates.

Use case: When you only want to react to specific state changes, rather than all signals.

Example:

// Before
Text(counter.value.toString())

// After
JoltSelector(
  selector: (prev) => null,  // Fill in the selector logic
  builder: (context, state) => Text(counter.value.toString())
)

Wrap with SetupBuilder

Wrap a widget with SetupBuilder to use Jolt's Setup pattern.

Use case: When you want to organize widget reactive logic using the Setup pattern.

Example:

// Before
MyWidget()

// After
SetupBuilder(setup: (context) { return ()=> MyWidget()})

⚠️ Lint Rules

no_setup_this

Prohibits direct or indirect access to instance members in the setup method (via this or implicit access).

Rule Description:

This rule ensures that instance members can only be accessed through the props parameter in the setup method, maintaining the purity and testability of the Setup pattern.

Checks:

• ❌ Explicit use of this.field or this.method()
• ❌ Implicit access to instance members (e.g., directly using field or method())
• ❌ Assigning this to a variable
• ❌ Assigning this to a setter

Correct Example:

class MyWidget extends SetupWidget {
  int count = 0;
  
  @override
  Widget setup(BuildContext context, MyWidget props) {
    // ✅ Access instance members through props()
    return Text(props().count.toString());
  }
}

Incorrect Example:

class MyWidget extends SetupWidget {
  int count = 0;
  
  @override
  Widget setup(BuildContext context, MyWidget props) {
    // ❌ Cannot directly access this.count
    return Text(this.count.toString());
    
    // ❌ Cannot implicitly access count
    return Text(count.toString());
  }
}

Quick Fix Support:

This rule provides automatic fixes to quickly transform incorrect code into the correct form:

• 🔧 Single Fix: Place the cursor on the problematic code, press Ctrl+. (or Cmd+.) and select "Replace this with props()" or "Add props() to the member" to automatically fix it
• 🔧 Bulk Fix: The fix menu also provides a "Fix all setup this issues" option to fix all related issues in the file at once

⚠️ Note: Due to a bug in the analysis_server_plugin package, the multi-fix in file feature may not work properly. If you don't see the "Fix all setup this issues" option, you may need to apply a temporary workaround. See fix_all_patch.md for details.

Fix Example:

// Before
Widget setup(BuildContext context, MyWidget props) {
  return Text(this.count.toString());
  // or
  return Text(count.toString());
}

// After
Widget setup(BuildContext context, MyWidget props) {
  return Text(props().count.toString());
}

Usage

After configuration, your IDE (e.g., VS Code, Android Studio) will automatically provide:

• Code Assists: Place the cursor on a variable or widget, press Ctrl+. (or Cmd+.) to view available transformation options
• Real-time Checks: Code that violates the no_setup_this rule will display error hints and automatic fix suggestions

License

MIT License