ResponseHandler Utility

ResponseHandler is a lightweight JavaScript utility designed to standardize response structures in your application. It helps ensure consistency and clarity when returning success, error, or validation responses from APIs or internal services.

Features

1. Success Responses: Return a structured success response with optional metadata.
2. Error Responses: Handle errors with detailed messages, custom error codes, and support for multiple errors.
3. Validation Errors: Provide a consistent format for validation-related errors.
4. Not Found Responses: Simplify responses for missing resources.
5. Custom Metadata: Include additional metadata like pagination details.
6. Centralized Logging (Optional): Log errors for debugging purposes.

Installation

Simply copy the ResponseHandler class into your project. You can also export it as a module if using a modern JavaScript environment.

Usage

1. Success Responses

const successResponse = ResponseHandler.success(
  { id: 1, name: "Sample Data" },
  "Data fetched successfully",
  200,
  { page: 1, limit: 10 } // Metadata
);
console.log(successResponse);

Output:

{
  "status": "success",
  "statusCode": 200,
  "message": "Data fetched successfully",
  "data": {
    "id": 1,
    "name": "Sample Data"
  },
  "meta": {
    "page": 1,
    "limit": 10
  }
}

2. Error Responses

const errorResponse = ResponseHandler.error(
  "Database connection failed",
  500,
  ["Connection timeout", "Invalid credentials"],
  "DB_CONN_ERROR"
);
console.log(errorResponse);

Output:

{
  "status": "error",
  "statusCode": 500,
  "message": "Database connection failed",
  "errorCode": "DB_CONN_ERROR",
  "errors": ["Connection timeout", "Invalid credentials"]
}

3. Validation Error Responses

const validationResponse = ResponseHandler.validationError(
  [{ field: "email", message: "Email is required" }],
  "Validation errors occurred"
);
console.log(validationResponse);

Output:

{
  "status": "fail",
  "statusCode": 400,
  "message": "Validation errors occurred",
  "errorCode": "VALIDATION_ERROR",
  "errors": [
    {
      "field": "email",
      "message": "Email is required"
    }
  ]
}

4. Not Found Responses

const notFoundResponse = ResponseHandler.notFound("User not found", 404, { userId: 123 });
console.log(notFoundResponse);

Output:

{
  "status": "error",
  "statusCode": 404,
  "message": "User not found",
  "meta": {
    "userId": 123
  }
}

Methods

success(data, message, statusCode, meta)

• data: (Object) The main response data.
• message: (String) A message describing the success.
• statusCode: (Number) The HTTP status code (default: 200).
• meta: (Object) Optional metadata (e.g., pagination).

error(message, statusCode, errors, errorCode)

• message: (String) Error message.
• statusCode: (Number) HTTP status code (default: 500).
• errors: (Array or Object) Details about the errors (default: []).
• errorCode: (String) A custom error code for debugging.

validationError(errors, message, statusCode, errorCode)

• errors: (Array) An array of validation errors (e.g., field-level errors).
• message: (String) A message describing the validation failure.
• statusCode: (Number) HTTP status code (default: 400).
• errorCode: (String) A custom error code (default: "VALIDATION_ERROR").

notFound(message, statusCode, meta)

• message: (String) A message describing the missing resource.
• statusCode: (Number) HTTP status code (default: 404).
• meta: (Object) Additional context for the not-found response.

Centralized Error Logging (Optional)

The logError method can be used to log errors for debugging purposes.

ResponseHandler.logError(errorResponse);

Contribution

Feel free to fork this repository and submit pull requests for additional features or improvements.

License

This utility is released under the MIT License. Use it freely in your projects.