Paul paulwongx

Air purfier electricity usage & Noise levels

Model	Mode	Power (W)	Noise (dB)
Levoit Core 400S	Sleep	3.3W	35dB
	Level 1	5.0W	42dB
	Level 2	8.0W	49dB
	Level 3	15.5W	58dB
	Level 4	38.8W	68dB
Coway Airmega 400S	Sleep	4.6W	34dB

Zod Error formats

Table of Contents:

Zod Error formats

Ahrefs SEO Toolbar
Keywords Everywhere
Meta SEO Inspector
Mozbar
NinjaOutreach Lite
Redirect Path
SEO Minion
SEOquake
Similarweb
Ubersuggest

Javascript Cheatsheet

This document focuses on more nuanced topics. It is not comprehensive.
Examples are taken from MDN mostly

Strings

// [@@iterator]() - iterating a string
const str = 'A\uD835\uDC68';
const strIter = str[Symbol.iterator]();

URL SHORTENER

Youtube URL: https://www.youtube.com/watch?v=JQDHz72OA3c

How to design a url shortener

Ask questions to clarify uncertainties

What is the length of the URL which is shortener
What is the volume of the traffic
Should this be a single system or scalable

-- CQLSH

-- creating keyspace
CREATE KEYSPACE dev_db WITH replication = {'class': 'SimpleStrategy', 'replication_factor': '1'} AND durable_writes = 'true';

-- consistency
CONSISTENCY; -- Current consistency level is LOCAL_QUORUM.
CONSISTENCY ONE; -- OK for one node
CONSISTENCY QUORUM; -- Best for multiple nodes at high replication factor of ~3

Object Oriented Programming

SOLID Principles

Single Responsibility Principle (SRP)
Open/Closed Principle (OCP)
Liskov Substitution Principle (LSP)
Interface Segregation Principle (ISP)
Dependency Inversion Principle (DIP)

Git Commands

# Checking out a new branch
git checkout -b <branch-name>
git checkout -b feature/my-feature

# Commiting a branch
git add .
git commit -m "Your commit message here"
git push origin <branch-name>

	<!DOCTYPE html>
	<html lang="en">
	<head>
	<meta charset="UTF-8">
	<meta http-equiv="X-UA-Compatible" content="IE=edge">
	<meta name="viewport" content="width=device-width, initial-scale=1.0">
	<title>Video Camera</title>
	<!-- Load TensorFlow.js. This is required to use coco-ssd model. -->
	<script defer src="https://cdn.jsdelivr.net/npm/@tensorflow/tfjs"> </script>
	<!-- Load the coco-ssd model. -->

	name: Deploy

	on:
	push:
	branches:
	- main

	jobs:
	deploy:
	runs-on: ubuntu-latest