Task 1: Create UserService class

• services/user.service.js

    const pool = require("../config/database");

    class UserService {
    
        constructor(){
            console.log("UserService constructor");
        }

        save(user){
            return new Promise((resolve,reject)=>{
                const params = [user.name, user.email, user.password, user.role];
                const query = 'insert into users (name,email,password,role) value (?,?,?,?)';
            
                pool.query( query, params, function (err, results) {
                    if (err) {
                        return reject(err);
                    } 
                    return resolve(results.insertId);
                })
            });
        }

        findAll(){
            return new Promise((resolve,reject)=>{
            
                const params = [];
                const query = 'select * from users';

                pool.query( query, params, function (err, results) {
                    if (err) {
                        return reject(err);
                    } 
                    return resolve(results);
                })
            });
        }

    }

    exports.UserService = UserService;

Test

    const { UserService } = require("../services/user.service");

    async function addUser() {
        const user = {
            name: "Naresh",
            email: "nareshkumarh2@live.com",
            password: "pass123",
            role: "ADMIN",
        };
        let userService = new UserService();
        try {
            const id = await userDAO.save(user);
            console.log("UserId", id);
        } catch (err) {
            console.error("catch block", err);
            console.error(err);
        }
    }

    async function listUsers() {
        let userDAO = new UserDAO();
        try {
            const users = await userDAO.findAll();
            console.log("Users", JSON.stringify(users));
        } catch (err) {
            console.error("catch block", err);
            console.error(err.sqlMessage);
        }
    }
    addUser();
    //listUsers();

• Test - Add User
• Test - List All Users