Error handling is a crucial aspect of building robust applications, and Express.js provides middleware for handling errors in a seamless manner. Ternary operations can be a powerful tool for simplifying our code and making it more concise. In this blog post, we will explore some tips for using ternary operations effectively in error handling middleware in Express.js.

1. Keep the code readable

While ternary operations can make our code more concise, it’s essential to prioritize readability. When writing error handling middleware, we should aim to make our code understandable for ourselves and other developers who may work on the project. Using descriptive variable names and adding comments can help improve readability.

app.use((err, req, res, next) => {
  const statusCode = err.status || 500;
  const message = err.message || 'Internal Server Error';

  // Ternary operation for handling response
  const response = err.response ? { error: err.response } : { message };

  res.status(statusCode).json(response);
});

In the example above, we use a ternary operation to check if the error object has a response property. If it does, we create a response object with the error, otherwise, we use the default error message.

2. Use ternary operations for conditional status codes

Ternary operations can be particularly useful when setting conditional status codes based on the type of error. For example, we might want to return a 404 status code for resource not found errors and a 400 status code for validation errors.

app.use((err, req, res, next) => {
  const statusCode = err instanceof NotFoundError ? 404 : 400;
  const message = err.message || 'Internal Server Error';
  
  const response = { error: message };

  res.status(statusCode).json(response);
});

In the above code snippet, we use a ternary operation to check if the err object is an instance of NotFoundError. If it is, we set the status code to 404; otherwise, we set it to 400. This approach allows us to handle different types of errors with appropriate status codes.

Conclusion

Ternary operations can be a handy tool for simplifying error handling middleware in Express.js. By keeping the code readable and using ternary operations for conditional status codes, we can make our code more concise and easier to maintain.

#expressjs #errorhandling