node-fullstack-sem-proj

Node fullstack semester project containing notes, thoughts and mandatory hand-ins.

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What is node?

Node is making it possible to run javascript on local machines without a browser - which means javascript can be used for setting up backend.
Running node will launch nodes runtime environment - then javascript code can be executed. REPL - Read Evaluate Print Loop. A REPL is an interactive programming environment that allows users to enter and execute individual lines or blocks of code, providing immediate feedback.

node

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HTML rendering

Html view is rendered procedural an example that can give some errors where the html tag is null - the js file will run before the html tag is created.

<script src="/assets/js/footer.js"></script>
<footer>
    <p id="copyright-year"></p>
 </footer>    

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The use of var

Don't use var it wont stick to its scope - it will polute outside its scope.

{
    {
        var someValue = false;
    }
    console.log(somevalue);
}

This will console log false because var polutes the scopes.

for (var i = 0; i <= 5; i++) {
    setTimeout(() => {
        console.log(i);
    })
}

6
        var someValue = true;
6
6
6
6
6

The print is because var polutes the scope that's why it prints 6 - if let is used the scope for i will stick for the console log inside the arrowhead function.

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Bonus notes

Const is constant NOT in the value but in the assignment, meaning that is cannot be reassigned and thus also HAS to be assigned.

• Javascripts functions is first-class citizens this mean:
• Functions can be assigned to a variable, allowing you to reference and call that function using the variable name.
• Functions can be passed as arguments to other functions.
• Functions can be returned from other functions.
• Functions can be stored in arrays, objects, or other data structures.

Javascript is hoisted (hoisting) - JIT (just in time compilation) reads all declarations and then execute statements. Because of that the below code will work:

getRandomInt();

function getRandomInt(min, max) {
    return Math.floor(Math.random() * (max + 1 - min) + min);
}

ABI: Application Binary Interface -> driver is just connection between codebase to DB.

CLI COMMANDS

Get PID for port 8080

lsof -i :8080

The npx standard command is used to run the standard package, which is a JavaScript style linter. Checking Code Style: The standard package is a JavaScript linter that enforces consistent coding style and catches stylistic errors in your code.

npx standard

dotenv is a popular package used for managing environment variables in Node.js applications. It loads environment variables from a .env file into process.env, making it easy to access and configure environment-specific settings such as API keys, database connection strings, and other configuration values.

npm install dotenv

// This code relies on dotenv and read and set secret from .env
import dotEnv from "dotenv";
dotEnv.config();

// This code does too
import "dotenv/config.js";

Working with crypto in node REPL to generate a random byte hex string:

node
require("crypto").randomBytes(36).toString("hex");

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Date With Javascript

DATES:

// UTC
console.log(new Date());

// Unix Epoch Time (Seconds since 1970 Jan. 1st -> the date is because that year unix was invented)
console.log(Date.now());

// Local time (in my case right now and here CEST GMT+0100)
console.log(Date());

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Nullish coalesce operator

// Nullish coalesce operator ?? ||
const value = undefined;

console.log(value ?? "some other value");
console.log(value || "some other value"); // type coerces ... takes falsy values and coerce

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Environment Variables for Nodejs

The process is only available within in Nodejs it's not a JavaScriptthing. It's important that the environment var is parsed before nodemon app.js is executed otherwise the environment var isn't valid.

# Execute app with nodemon and set the env PORT
PORT=9090 nodemon app.js

// Get env var called PORT
process.env.PORT

TO fix the problem where env var is instantiated differently for mac and windows - use cross-env to fix this issue https://www.npmjs.com/package/cross-env

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MONGODB

Starting the mongodb daemon -> be placed in ~/Downloads/mongodb-macos-aarch64-7.0.9/bin

./mongod --dbpath ./../../../Projects/mongodb_datastore/db

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LINKS

ESLINT: tool for making code more consistent and avoiding bugs - CLEAN CODE -> https://eslint.org/docs/latest/use/getting-started

CROSS-ENV: Fix issue with setting env var in script for mac / windows cross-env -> https://www.npmjs.com/package/cross-env

MAIL: Sending mails with NODEMAILER -> https://www.nodemailer.com

PM2: Production process manager PM2 - if application crash it will reinstatiate with PM2 -> https://www.npmjs.com/package/pm2

Express session -> https://www.npmjs.com/package/express-session

Rate limiter -> https://www.npmjs.com/package/express-rate-limit

Morgan - request middleware logger for node -> https://www.npmjs.com/package/morgan

Bcrypt -> https://www.npmjs.com/package/bcrypt

Helmet: helps secure Express apps by setting HTTP response headers -> https://www.npmjs.com/package/helmet

Escape html: show html as plain text for user inputs to avoid xss -> https://www.npmjs.com/package/escape-html

dotenv: to load variables from .env file -> https://www.npmjs.com/package/dotenv

svelte-navigator: navigation through routes for svelte pages -> https://www.npmjs.com/package/svelte-navigator

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Shortcuts

WHen inside markdown file press ctrl + shift + v then the file will be displayed with formatting. Pretty nice and convenient.

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MISCH / IMAGES