/n-custom-errors

Custom errors for Node.js

Primary LanguageJavaScriptMIT LicenseMIT

n-custom-errors

WARNING ⚠️: This repo is not maintained anymore.

Custom errors for Node.js.

Build Status Code Coverage npm version

Features

  • custom errors with name, code and error message.
  • template strings for formatting error messages.
  • helper functions for each registered error:
    • get<errorName>Error()
    • get<errorName>ErrorType()
    • is<errorName>Error()

Install

$ npm i n-custom-errors

Usage

// Registering errors:
customErrors.registerError('AccessDenied', 403);
customErrors.registerError('DuplicateObject', 409);
customErrors.registerError('ObjectNotFound', 404, '${objectName} not found');

// Creating custom errors:
let objectNotFoundError = customErrors.getObjectNotFoundError({ objectName: 'user' });
let duplicateObjectError = customErrors.getDuplicateObjectError('The email is not unique');

console.log(objectNotFoundError);
/*
prints => {
  name: 'ObjectNotFoundError',
  message: 'user not found',
  statusCode: 404
}*/
console.log(duplicateObjectError);
/*
prints => {
  name: 'DuplicateObjectError',
  message: 'The email is not unique',
  statusCode: 409
}*/

// Checking that an error is a custom error:
let err = new Error();
let objectNotFoundError = customErrors.getObjectNotFoundError({ objectName: 'user' });
customErrors.isObjectNotFoundError(err)); // returns false
customErrors.isObjectNotFoundError(objectNotFoundError)); // returns true

API

  • registerError(name, statusCode, messageTemplate)
    Registers a new custom error.

    • name - error name, required, must be an unique. Name must be without Error postfix.
    • statusCode - http status code for error.
    • messageTemplate - template for a message, must contains parameters in the following format: ${objectName} not found. To pass the parameters to the template, parameters must be an object with defined properties: customErrors.getObjectNotFoundError({ objectName: 'user' }). If parameters is a string, than this string will be used in an error message without template: customErrors.getObjectNotFoundError('User with a name user1 not found, please use another filter').

  • isKnownError(err)
    Returns true if err is a registered custom error, false otherwise.

    • err - error object, required.

  • get<errorName>Error(msg)
    This function is added automatically when a new custom error is registered.
    Creates a custom error with message msg, it can be the parameters object if an error is registered with messageTemplate.

    • msg - an error message, required.

  • get<errorName>ErrorType()
    This function is added automatically when a new custom error is registered.
    Gets a custom error type.

  • is<errorName>Error(err)
    This function is added automatically when a new custom error is registered.
    Returns true if err is a custom error, false otherwise.

    • err - error object, required.

License

Licensed under the MIT license.

Author

Alexander Mac