Goal

• Separate error handling logic code

Existing Code : app.js contains global error handler logic

     require('dotenv').config()
    const express = require('express')
    const app = express()
    const port = process.env.PORT
    app.use(express.json())

    // Create Routes
    const apiRoutes = require('./router');
    app.get('/api', apiRoutes);
    
    // Create Commmon Error Handler
    app.use(function (err, req, res, next) {
        console.log("common error handler")
        console.error(err);
        res.status(500).json({errorMessage:err.message});
    })

    app.listen(port, () => console.log(`app listening on port port!`))

Task : Separate error handler

• error-handler.js

    function handleError (err, req, res, next) {
        console.log("common error handler")
        console.error(err);
        res.status(500).json({errorMessage:err.message});
    }

    module.exports = handleError;

• app.js

  const handleError = require("./error-handler")
  app.use(handleError);