DEV Community: christosmito

Bottom values in Javascript

christosmito — Sat, 01 May 2021 15:55:37 +0000

Javascript has two bottom values. The null and undefined values are considered javascript's bottom values that indicate the absence of a value. In addition, these values are the only values in javascript that are not object. Attempting to get a property from them raises an exception. Even though the null is a well known value in other languages and it is commonly used, in javascript it is considered best practice to use undefined in most cases. First let's see the only case that we can use null instead of undefined. Using Object.Create(null) in order to create a new empty object. So, why we should use undefined? Because javascript itself uses this value. If you define a non-initialize variable with let and var their values are undefined. If you do not pass enough arguments into a function, if you request a property from an object that lacks that property and if you get an element of an array that the array lacks, javascript gives undefined. We can make better programs if we eliminate one of them not from the language 😛 but from our programs

My first npm package about authentication

christosmito — Tue, 27 Apr 2021 19:47:15 +0000

Intro

I have been coding in Express and Mongodb about 1,5 years now and on every project I have built up until now I had to write the same code again and again in order to implement the authentication. Repetition is something we, as programmers, hate. So, for that reason I decided to make my own authentication package in order to implement the authentication flow and the DRY principle.

Implementation

This npm package was built to be used with Express and Mongodb. The authentication is based on jwt. In addition, sendgrid was used to implement the reset password functionality for sending an email with the reset token link.

Usage

This package offers the below functionalities:

signup
login
logout
update password
forgot password

Let's see how easily we can use this package:
First we need to install the express-auth-flow package with this command

npm install express-auth-flow
or
yarn add express-auth-flow

Then we need to create a user model with the name of our choice and create at least these fields(the names must be exactly the same) as shown below:

email
username
password

Below is demonstrated a simple example using mongoose(it is highly recommended to validate all the fields)

//Model file userModel.js

const mongoose = require("mongoose");

const { Schema } = mongoose;

const userSchema = new Schema({
    email: String,
    username: String,
    password: String
});

module.exports = mongoose.model("User", userSchema);

Now in your router file you must require your user's model you created above, the express-auth-flow package and make routes as below. The paths and the names must be exactly the same in order the package to recognize them. The email for the forgot password functionality are sent via sendgrid and you have to create a free account and then create an api key. An example is shown below:

//Router file userRoutes.js

const express = require("express');

const User = require("The path to your user model");

const auth = require("express-auth-flow");

const router = express.Router();

//Only for forgot password functionality
const options = {
    apiKey: "your sendgrid api key",
    from: "your email that you verified on sendgrid",
    text: "The raw message",
    html: "The html formatted message"
};

router.post("/signup", auth("User").signup);
router.post("/login", auth("User").login);
router.post("/logout", auth("User").logout);
router.post("/update-password", auth("User").updatePassword);
router.post("/forgot-password", auth("User, options").forgotPassword);
router.post("/reset-password/:token", auth("User").resetPassword);

module.exports = router;

Finally lets analyze the inputs that are expected from every router

/signup

The signup functionality is expect the below input:
email, username, password, confirmPassword

/login

The login functionality is expect the below input:
email, password

/logout

No input

/updatePassword:

email, password, newPassword, confirmNewPassword

/forgot-password

/reset-password/:token

password, confirmPassword

Notice

The forgot password functionality works like this:
First the user goes to /forgot-password route and fills the
email, password, newPassword, confirmNewPassword inputs. Then an email is sent to the provided email with a reset token link that is valid for 10 minutes and when the user redirects to this link must provide the password and the confirmPassword in order to save new password.

In the near future I am going to release a video tutorial on how to use this package

Thanks for your time and feel free to write any feedback.
contact me at this email: christosglx@hotmail.com

Questions about personal project. MongoDB(Mongoose)

christosmito — Wed, 29 Jul 2020 08:11:56 +0000

Hello! I am considering to start a personal project both for demonstration and learning purposes. The technologies I am going to use is node.js(express.js) mongoDB(mongoose) and puppeteer. The project is that, I will scrape some sites and store the information in a database. For instance I will scrape some websites that sell tech stuff. I have some questions about the implementation.
1) What is better? To store all the data to one single model or to construct different models for different categories. For example I will have a model for mobile phones a model for laptops and so on, or just one big model with a category attribute and write the category in it.
2) Is any package or tutorial about partial text search in mongoDB or is better to use something like elasticSearch?
3) In my example is it possible when the user search for a “general” product to return only the categories and not all the related products? For example if I search for iphone 11 in this site https://www.skroutz.gr/c/40/kinhta-thlefwna.html?keyphrase=iphone+11 it will return only the deferent categories about iphone 11 and not all the products from all the stores. Is it possible in mongoDB?