error-ex

What is error-ex?

The error-ex npm package is designed to create more customizable and informative error objects in JavaScript. It allows developers to extend the native Error type with additional properties and behaviors, making error handling and debugging more efficient.

What are error-ex's main functionalities?

Creating custom error types

This feature allows developers to create custom error types by extending the native Error object. The custom error can then be thrown with a specific message, making it easier to identify and handle specific kinds of errors in the code.

const ErrorEx = require('error-ex');
const MyError = ErrorEx('MyError');
throw new MyError('Something went wrong');

Adding properties to errors

This functionality enables the addition of custom properties to error objects. In this example, a 'code' property is added to a custom error type, which could be used to store HTTP status codes or other relevant error information.

const ErrorEx = require('error-ex');
const MyError = ErrorEx('MyError');
MyError.prototype.code = 404;
const errorInstance = new MyError('Resource not found');
console.log(errorInstance.code); // 404

Other packages similar to error-ex

verror

VError is a library for richer JavaScript errors. It allows chaining of errors, providing a way to wrap lower-level errors without losing the original context. Compared to error-ex, VError focuses more on error wrapping and context preservation.

http-errors

http-errors is a package for creating HTTP error objects. It is specifically tailored for use in web applications, providing a straightforward way to create errors with HTTP status codes. Unlike error-ex, http-errors is more specialized for HTTP applications.

README

node-error-ex

Easily subclass and customize new Error types

Examples

To include in your project:

var errorEx = require('error-ex');

To create an error message type with a specific name (note, that ErrorFn.name will not reflect this):

var JSONError = errorEx('JSONError');

var err = new JSONError('error');
err.name; //-> JSONError
throw err; //-> JSONError: error

To add a stack line:

var JSONError = errorEx('JSONError', {fileName: errorEx.line('in {}')});

var err = new JSONError('error')
err.fileName = '/a/b/c/foo.json';
throw err; //-> (line 2)-> in /a/b/c/foo.json

To append to the error message:

var JSONError = errorEx('JSONError', {fileName: errorEx.append('in {}')});

var err = new JSONError('error');
err.fileName = '/a/b/c/foo.json';
throw err; //-> JSONError: error in /a/b/c/foo.json

License

Licensed under the MIT License. You can find a copy of it in LICENSE.