How to Use CreateError for Crafting Custom Error Classes in Node.js

The npm createerror package is a helper that allows you to easily create custom error classes in Node.js. It provides a simple API to define and extend error classes with customizable properties and methods.

CreateError Installation

Node.js and npm should be installed before using the createerror package. To install createerror, the following command should be run:

npm install createerror

CreateError Example

Here’s a simple example on how to use createerror in Node.js:

var createError = require('createerror');

var MyError = createError({
    name: 'MyError',
    message: 'Message describing the error'
});

In the above example, the createerror package is used to create an error called MyError that has the name and message properties.

How to Throw Errors Using CreateError

After a custom error has been created using the createerror package, an instance of it can be thrown using the JavaScript throw keyword. Any instances of the error can also contain extra data about the error.

Here’s an example that throws an instance of the MyError error created above:

try {
    throw new MyError({
        message: "My message",
        data: {restrictedIds: [1, 2, 3, 5]}
    });
} catch(e) {
    console.error(e.data);
}

Here, the MyError instance created in the try block contains a property called data that contains a set of restrictedIds. The error is caught in the catch block and the output is logged to the console with the error’s data property:

{ restrictedIds: [ 1, 2, 3, 5 ] }

Track, Analyze and Manage Errors With Rollbar

As you can see, creating custom errors can provide more detailed and meaningful error information. However, even with the best error handling in place, errors can still slip through. That's why it's beneficial to use a robust error monitoring solution.

If you're interested in improving your application's error handling, I would highly recommend checking out the Rollbar error monitoring SDK. Rollbar provides real-time error tracking & debugging tools for developers. It's language agnostic and can be used with JavaScript, Python, Ruby, Java, .NET, and more. Try it today!