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ErrorHandler & ErrorLoggerHandling

Implementation of error management as well as the creation of a log file that is automatically generated when the API receives an error.

Be careful first of all, you have to think about creating a log folder in the root

Creating the errorHandler file

Creation of an ErrorApi class which extends on the parent the generic Error constructor, which will allow us to automate and instantiate the errors encountered.

Import

import { errorLoggerHandling } from '../../app/services/errorLoggerHandling.js';
import { Request, Response } from 'express';

class ErrorApi

class ErrorApi extends Error {
  constructor(message: string, req: Request, res: Response, statusCode: number = 500) {
    super(message);
    res.status(statusCode).json({ message: message });

    //~ Log errors
    errorLoggerHandling(message, req, res);
  }
}

export { ErrorApi };

Creating the formattedDate file

/utils/formattedDate.js

//~ NEW DATE (Format)
const today = new Date();

const day = today.toLocaleString('en-EN', { day: 'numeric' });
const month = today.toLocaleString('en-EN', { month: 'numeric' });
const year = today.toLocaleString('en-EN', { year: 'numeric' });

const formattedDate = [year, month, day].join('-');

export { formattedDate };

Creating the errorLoggerHandling file

Import

//~ Import modules
import { formattedDate } from '../utils/formattedDate.js';
import { Request, Response } from 'express';
import * as fs from 'fs';

//~ Resolve __dirname
import { resolve, join } from 'path';
const __dirname = resolve(`./src/app/services`);
// resolve will define your root file

//~ Logger
import debug from 'debug';
const logger = debug('ErrorHandling');

Function errorLoggerHandling - Manage error

Creation of a function which allows to create a log file to generate the date and also its content which includes, date, time, path, and the error

function errorLoggerHandling(message: string, req: Request, res: Response) {
  const actualDate = new Date();

  // format error message : Date + url + message
  // 00/00/0000 00:00:00 - /api/v1/{path} - "My error"
  const logMessage = `${actualDate.toLocaleString()} - ${req.url} - ${message}\r`;

  // date format YYYY-MONTH-DD
  const fileName = `${formattedDate}.log`;

  // create a log and write it in your file
  fs.appendFile(join(__dirname, `../../../logs/${fileName}`), logMessage, (error) => {
    if (error) logger(error);
  });
}

export { errorLoggerHandling };

Example errorHandler in controller

Example import

import { ErrorApi } from '../services/errorHandler.js';

Examples of uses

//~ Guard Clauses
if (userId !== userExist.id) throw new ErrorApi(`Given informations not allows any modification`, req, res, 403);

//~ Error 404 NOT Found
app.use((req, res) => {
  throw new ErrorApi(`Page not found !`, req, res, 404);
});

Final render

Example of file generated in the log folder:

2022-9-13.log

And its content:

13/09/2022 08:44:58 - /favicon.ico - Page not found !
13/09/2022 09:59:24 - /api/v1/categories - No tokens found !

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