@loxjs/errors NPM

@loxjs/errors

@loxjs/errors is a Node.js module designed to create a standardized error handling system. It extends the native JavaScript Error object, providing additional properties such as internal and HTTP status codes, and integrates with Express.js for handling errors in web applications.

Features

Extends the native Error object with additional properties and methods.
Provides a unified way to handle different types of errors.
Allows for internationalization (i18n) of error messages.
Supports custom error details and data payloads.
Integrates with Express.js to handle errors in HTTP requests.
Can generate both detailed and simplified error JSON representations.

Installation

Install the package with npm:

npm install @loxjs/errors

Or with yarn:

yarn add @loxjs/errors

Usage

Basic Error Creation

const Errors = require('@loxjs/errors');

// Create a new error
const myError = new Errors('MyCustomError', {
  message: 'Something went wrong',
  httpCode: 400,
  detail: 'Detailed information about the error',
  data: { additional: 'data' }
});

console.log(myError.toJSON()); // Outputs the error as a JSON object

Express.js Middleware

const express = require('express');
const app = express();
const { expressError } = require('@loxjs/errors');

// Use the middleware in your Express application
app.use(expressError({
  isPROD: process.env.NODE_ENV === 'production', // Use true to hide detailed error info in production
  errHandler: (errJSON) => {
    // Optional: A function to handle the error, e.g. logging it
    console.error(errJSON);
  },
  i18n: (code) => {
    // Optional: A function for internationalization
    return code; // Replace with actual i18n implementation
  }
}));

app.get('/', (req, res) => {
  throw new Error('Oops!'); // This will be caught by the expressError middleware
});

app.listen(3000);

Error Wrapper

const { errorWrapper } = require('@loxjs/errors');

// Wrap native errors or custom error codes
const wrappedError = errorWrapper('CustomErrorCode', {
  message: 'Custom error message',
  httpCode: 500
});

console.log(wrappedError.toString()); // Outputs the error as a JSON string

Internationalization

const { setI18n } = require('@loxjs/errors');

// Set an internationalization function
setI18n((errCode) => {
  const i18nMessages = {
    'CustomErrorCode': 'Translated custom error message',
    // Add more error code translations here
  };
  return i18nMessages[errCode] || errCode;
});

API Reference

Errors Class

new Errors(code, options)
- code (String): The error code.
- options (Object): Additional options for the error.
  - internalCode (String): Internal error code for debugging.
  - httpCode (Number): HTTP status code associated with the error.
  - message (String): Human-readable description of the error.
  - fileName (String): Name of the file where the error occurred.
  - lineNumber (Number): Line number where the error occurred.
  - stack (String): Stack trace.
  - detail (Any): Additional details about the error.
  - data (Any): Additional data payload.

errorWrapper Function

errorWrapper(loxErrorCodeOrNativeErrorEntity, optionsOrErrorMessage)
- Wraps a custom error code or native error entity into a standardized error object.
- loxErrorCodeOrNativeErrorEntity (String|Error): The error code or native error object.
- optionsOrErrorMessage (Object|String): Additional options for the error or a message string.

expressError Middleware

expressError(options)
- options (Object): Configuration options for the middleware.
  - isPROD (Boolean): Whether to run in production mode, which affects error detail visibility.
  - errHandler (Function): A function to handle the error, such as logging.
  - i18n (Function): A function for internationalizing error messages.