eslint-plugin-named-functions-in-hooks

This ESLint plugin enforces the use of named functions instead of anonymous functions in React hooks such as useEffect, useCallback, and useMemo. Using named functions improves readability, debugging, and reusability of code within React components.

Why Use This Plugin?

Benefits of Named Functions in Hooks:

1. Improved Debugging:
   • Named functions appear in stack traces, making debugging easier.
2. Code Reusability:
   • Reusable named functions prevent redundant logic and improve maintainability.
3. Readability:
   • Makes the intent of the function clearer, especially in complex components.

Installation

Install the plugin via npm:

npm install eslint-plugin-named-functions-in-hooks --save-dev

Usage

To enable the plugin in your ESLint configuration, add it to the plugins array and define the rule under rules:

Example .eslintrc.json:

{
  "plugins": ["named-functions-in-hooks"],
  "rules": {
     "named-functions-in-hooks/named-functions-in-hooks": "error"
  }
}

Rule Details

Rule: named-functions-in-hooks

This rule ensures that only named functions are passed to React hooks (useEffect, useCallback, useMemo).

Default Behavior

• Disallows anonymous arrow functions and function expressions in the listed hooks.
• Allows named functions and functions imported from other modules.

Examples

✅ Correct Code:

Using named functions improves readability and debugging:

Named Function in useEffect:

  function logEffect() {
    console.log("Effect executed");
  }

  useEffect(logEffect, []);

  // or 

  React.useEffect(logEffect, []);

Named Function in useCallback:

  function memoizedHandler() {
    console.log("Handler executed");
  }

  const handler = useCallback(memoizedHandler, []);

  // or

  const handler = React.useCallback(memoizedHandler, []);

Named Function in useMemo:

  function computeExpensiveValue() {
    return someHeavyCalculation();
  }

  const memoizedValue = useMemo(computeExpensiveValue, [dependencies]);

  // or

  const memoizedValue = React.useMemo(computeExpensiveValue, [dependencies]);

❌ Incorrect Code:

These examples will trigger an ESLint error:

Anonymous Function in useEffect:

  useEffect(() => {
    console.log("Effect executed");
  }, []); // Error: Only named functions are allowed in useEffect.

  // or 

  React.useEffect(() => {
    console.log("Effect executed");
  }, []); // Error: Only named functions are allowed in useEffect.

Anonymous Function in useCallback:

  const handler = useCallback(() => {
    console.log("Handler executed");
  }, []); // Error: Only named functions are allowed in useCallback.

  // or 

  const handler = React.useCallback(() => {
    console.log("Handler executed");
  }, []); // Error: Only named functions are allowed in useCallback.

Anonymous Function in useMemo:

  const memoizedValue = useMemo(() => someHeavyCalculation(), [dependencies]); // Error: Only named functions are allowed in useMemo.

  // or

  const memoizedValue = React.useMemo(() => someHeavyCalculation(), [dependencies]); // Error: Only named functions are allowed in useMemo.

How It Works

The plugin defines a custom ESLint rule that:

1. Targets specific React hooks (useEffect, useCallback, and useMemo).
2. Checks the first argument of the hook to determine if it is an anonymous function.
3. Reports an error if the argument is an anonymous function.

The rule works with both functional and class components.

Configuration Options

Currently, the rule does not support additional configuration. Future updates may add customization options (e.g., extending the list of hooks).

Contributing

We welcome contributions to improve the plugin! Here’s how you can get started:

1. Fork the repository and clone it locally.

2. Install dependencies:

   npm install

3. Implement your changes in the appropriate file (e.g., add a new feature or fix a bug).

4. Write tests to ensure your changes work as expected.

5. Open a pull request for review.

## License

This project is licensed under the MIT License.

Feedback and Issues

If you encounter any issues or have suggestions for improvement, please open an issue in the GitHub repository.

We’d love to hear your feedback and ideas!