标签：#beginners

1. Introduction Hello from Japan! 🇯🇵 I am an active truck driver in Japan self-studying Python and Web technologies, leveraging my logistics domain knowledge to transition into a Web Engineer. (English is my second language, but I'm excited to share my progress with developers worldwide!) I started my learning journey on May 12, 2026. As of June 4, I have logged 24 days and 86 cumulative hours of study. This article documents my progress, learning roadmap, and project milestones chronologically. Check out my GitHub here👈️ (Note: Most repository documentation and commit messages are currently in Japanese.) 2. The 86-Hour Learning Roadmap A quick breakdown of my 86 hours: 80 hours were dedicated to hands-on development and implementation, and 6 hours were spent on environment configuration, documentation, and workflow optimization. Stages 1–3: Automation & Scraping Projects ① Fundamentals & Web Scraping (25 hours) Learned core Python syntax and built automated scripts to collect targeted web data. ② Puoppo Auto-Analysis System (15 hours) Implemented automated poll data retrieval and AI-powered text analysis on Lubuntu. ③ Bakery Sales Aggregation System (12 hours) Integrated web scraping with automated Excel processing to streamline sales data aggregation. Stage 4: Practical Ruby on Rails ④ rails_practice (23 hours) Explored MVC architecture in Ruby on Rails. Practiced configuration management and Git rebasing to build a solid foundation in web framework operations. Stage 5: Real-World System Integration ⑤ hiroshima-logistics-hub (5 hours) Built a web system to aggregate real-time weather and traffic conditions in the Hiroshima area. Technical Fix : To bypass build crashes on Render (Free Tier / 512MB RAM), I precompiled assets locally and configured SQLite3 database storage in writable directories before deployment. 3. Key Takeaways for Resource-Constrained Development Through these projects, I established three operational principles for developing efficiently within

Last time I said each post would show you the receipts. This one is a single day's worth. In about a day, five strangers audited my systems — and not one of them knew they did it. Each was a comment or a post on this feed: a single sentence that turned out to be pointing straight at a hole in something I'd already shipped and already trusted. I read the sentence, found the hole, and closed it — usually within the hour. I'm a physical therapist who builds a hospital's internal tools with AI, so "closed it" means the AI and I closed it while I described what was actually breaking. Five sentences, five holes, five receipts. They also turned out to be one idea wearing five coats. I'll get to that. Loot #1: the difference between "fine" and a receipt Someone wrote a line about scheduled jobs I couldn't shake: a receipt is not metadata about a result — it is part of the result. Labels go stale silently, they said, because whatever wrote the label already walked away before it stopped being true. My systems' health check said ok . That was the whole thing — a green word. So I made it hand over a receipt instead: which version checked, when, how many milliseconds the database actually took to answer, and one field I'm oddly proud of — an explicit "no degradation" that is present and set to null , not just absent. That distinction sounds like nothing and is everything: a missing field means "nobody checked," a field that's present-and-null means "checked, and it was clean." One is silence wearing a confident face. The other is proof someone looked. My health check used to conflate them. Now it can't. Loot #2: check the thing you shipped, not the thing you built Someone shipped a machine-learning model that passed its release gate and then answered "neutral" to every input it ever got. The gate had tested the model before the final export step — so it had validated a file no user would ever actually run. Their line: ask whether your gate validates the file you upload. I had t

You don't need a cloud server to start learning Linux administration. A few days ago, I came across a LinkedIn post by Luiz Fernando dos Santos about turning an old Android phone into a Linux server using Termux. Reading his post made me wonder: Do I really need to pay for a VPS just to learn Linux and server administration? The answer, at least for now, seems to be no. Inspired by his idea, I decided to build my own learning environment using nothing but an Android phone and Termux. This article is the beginning of a series where I'll document everything I learn along the way. Inspiration Before getting started, I'd like to give credit to Luiz Fernando dos Santos, whose LinkedIn post inspired this project. His idea of using an old Android phone as a Linux server showed me that I didn't need to rent a VPS to start learning Linux administration. You can check out his original post here: 🔗 https://www.linkedin.com/pulse/transformando-um-android-antigo-em-servidor-luiz-fernando-dos-santos-gu1if/ First Steps I had already been using Termux for quite some time, so the first thing I did was update all the installed packages. apt update apt upgrade -y After that, I installed OpenSSH. pkg install openssh Before moving on, I wanted to understand what SSH actually is instead of just following commands from a tutorial. SSH (Secure Shell) is a protocol that allows you to securely connect to another computer or server through an encrypted connection. It's one of the most common ways to remotely access Linux servers. After installing it, I found the Termux username, configured a password and started the SSH server. Then I tried connecting from my computer... And it worked! It may sound like a simple thing, but seeing my computer remotely access the Linux environment running on my phone was surprisingly satisfying. Improving the Authentication After getting the basic connection working, I started researching how authentication by SSH keys works. I learned that instead of typing a

Hey Techie! 🌸 Welcome to my Go series! I'll be sharing what I'm learning in ways that make sense to me, the mistakes I make and the "aha!" moments that help everything click. Whether you're learning Go too or just curious about it, I hope you'll pick up something along the way. Feel free to add any insights or experiences in the comments. Today's topic is... drumroll, please! Slices . Let's dive in! So, what exactly is a slice? When I first came across slices in Go, I thought they were another name for arrays. Turns out, they're not! A slice is internally represented by a small data structure called a slice header . Instead of storing the elements themselves, the slice header stores a pointer to the underlying array, along with its length and capacity . This realization helped me understand why modifying a slice can also modify the original array. Another interesting and convenient thing is how flexible slices are compared to arrays which are fixed size. Slices can grow using functions like append() or be resliced to work with a smaller portion of the underlying array. This flexibility is one of the reasons slices are used so frequently in Go.

Before I hand this over, I want to tell you where I'm actually standing right now. I'm looking at the biggest mountain yet: building our hospital's own ERP and EMR — the systems that run the business side and the medical records side of the whole place. That's usually the job of specialized companies, and it's tangled up with outside regulators too. Nobody knows how long it'll take. I'm assuming at least three years. Honestly, it feels overwhelming. The size of the fear hasn't changed. My grip on it has. Here's the strange part. That overwhelmed feeling isn't unfamiliar at all. A year ago, staring at a blank screen and not knowing what code even was, I felt exactly this lost. What's different isn't the size of the fear. It's that I now know what to do with it. Get curious, look it up. Look it up, a direction shows up. See a direction, find a method, and just start. Fail, and you've learned something. Succeed, and you move to the next thing. That loop is the only thing that ever carried me anywhere , and it's the same loop I'm running at the foot of this much bigger mountain. Right now the wall isn't technical The thing I don't know isn't code. It's other departments. I moved from the treatment room to the planning office not long ago, and I still don't really know how the other departments do their work. You can't automate what you don't understand. So before anything else, I'm doing the one thing that actually comes first: listening. Hearing what people in the field actually need, what's grinding on them, and figuring out the shape of a fix together, one conversation at a time. I've noticed something before, more than once: problems that look completely different from the outside — counting a stack of forms, tracking down misplaced supplies, sorting a pile of ID cards — usually reduce to the exact same shape underneath. Make the pile of things findable. I suspect the same pattern is waiting inside every other department too. I just haven't looked yet. That's how I

Hello, I'm Maneshwar. I'm building git-lrc, a Micro AI code reviewer that runs on every commit. It is...

Como eu mostro que estou contribuindo? Posso colocar no meu LinkedIn? E no meu currículo, como faço? Foi a partir dessas dúvidas que eu elaborei esse guia pra você que quer contribuir do seu jeito e mostrar às empresas e às pessoas, de forma clara e estratégica, o que você está fazendo. Vamos lá? 👇 Por que eu deveria mostrar no LinkedIn? LinkedIn é a porta de entrada para o mundo corporativo no Brasil e no mundo. É por meio dele que você mostra "trabalho". E tem mais: não é só experiência remunerada que conta como evidência de que você tem conhecimento e prática, mas também tudo o que você constrói de forma voluntária , seja tirando dúvida de alguém, participando de um projeto open-source ou escrevendo sobre o que aprendeu. Recrutador não lê currículo pensando só em carteira assinada. Lê pensando em capacidade . Você contribui com algo para a comunidade e quer colocar isso no seu perfil. Existem 3 formas que você pode usar, e elas podem ser usadas todas juntas ou só uma. Escolha aquela que fizer mais sentido pro seu perfil ou busque por outras pessoas que você admira dentro da comunidade e veja como elas colocaram no próprio perfil. 1. Seção de Experiência Use como experiência sempre que estiver contribuindo de forma profissional pra uma área que você busca. Se você participa de contribuições no GitHub, seja através de código, documentação ou outra forma, use como experiência. Pessoas que também estão ajudando na moderação ou administração (community managers) podem destacar as responsabilidades ou resultados das suas ações por aqui. Exemplo de como preencher no LinkedIn: Cargo: [cargo que você faz] Open Source Empresa: [Nome do projeto/organização] Tipo de emprego: Meio período (ou Voluntário) Local: Remoto, Brasil Descrição: - Contribuí com [X] pull requests na documentação do projeto [Nome], focando em clareza para novos contribuidores. - Revisei issues abertas e sugeri melhorias de acessibilidade em componentes de UI usando [ferramenta/stack]. - Participei de re

After spending 2 years building an image compression tool, here's my no-nonsense format guide. ## The Rule | If it's... | Use... | |---|---| | Logo, icon, screenshot | PNG | | Photo, everyday image | WebP | | Smallest possible file | AVIF | | Maximum compatibility | JPEG | ## Why? PNG — Lossless. Keeps text and sharp edges crisp. Supports transparency. But files are large for photos. JPEG — Works literally everywhere since 1992. Good compression for photos. No transparency support. At 80-85% quality, the visual difference from 100% is invisible but the file is half the size. WebP — The sweet spot. 25-35% smaller than JPEG with same quality. Supports both lossy and lossless. Supports transparency. Every modern browser supports it now (97%+ global coverage). For most websites, this is the right answer. AVIF — The next-gen format. 50% smaller than JPEG, 30% smaller than WebP. Supports HDR, 12-bit color, and both lossy/lossless. The catch: not supported on older devices (iOS 15 and below). Use it with a <picture> fallback. ## Real Numbers I ran the same photo through all four formats at comparable quality: JPEG (90%): 842 KB PNG: 3,241 KB WebP (90%): 547 KB AVIF (90%): 382 KB WebP cut the JPEG size by 35%. AVIF cut it by 55%. ## What I Recommend I built CompressFast ( https://compressfast.site ) — a free browser-based image compressor that handles all these formats. No uploads, no servers, everything runs locally.

This week I accidentally created my first vibe coded application. You might ask how one does this accidentally, but it's actually easier than you think. Assumptions Made: The first mistake I made was to assume that Claude remembered my setup and how I like to pair program. I have only had one previous project coded with the help of Claude and GHCP and it's a much more basic application than what I was building this week. I assumed, incorrectly, that Claude would 'remember' how I liked to work and go through the project with me as we make decisions and coding blocks together. The other assumption I made was giving a somewhat blanket approval for Claude to just run with things. I thought at some point Claude would stop, check its understanding during development and then continue but I got excited at the idea of using subagents and once I'd selected that option there was no stopping Claude on its rampage through my code! So What's the Project? I've recently started looking at doing more work with AI rather than just prompting Claude or GHCP to help with the day to day. I wanted to actually call an LLM and sift through information which could then be saved in a DB and recalled at a later point. I set myself a four week plan (with the help of Claude) to help solidify my learning with week one being a basic console application in C# that takes some text, sends to an LLM and then extracts certain information, in this case names of people, which is saved into a Postgres database. Sounds simple right? Where things went right This project started off very interesting. I had a conversation with Claude, same as I would with another developer, about the right LLM to use for this project. We went through the positives, negatives and the potential cost benefits and pitfalls of each option. In the end it was narrowed down to two choices, OpenAI or Gemini. Given that I was experimenting quite a bit and I didn't want to accidentally run up costs, I decided to go with Gemini's free t

I came to dev.to to translate. I stayed to steal. I mean that as the compliment it is here. On this site, "I'm stealing that line" is something you say to an author's face and they thank you for it. Ideas are meant to be lifted, reused, carried home. It took me a while to understand that culture — because I didn't arrive as a thief. I arrived as a tourist who couldn't read the signs. Here's the setup. I'm Korean. My English is workable but slow, and writing a comment good enough to earn a real reply from a stranger — in a second language, in a technical field I never trained in — is more than I can do alone at a speed I'd tolerate. So when I started reading and commenting here, I opened an AI beside me and used it the obvious way: as a translator. Read the post, get the gist, draft a reply, fix my English, post it. That was the whole plan. It lasted about a week. The moment the tool changed jobs What broke the plan was that the posts were good . Not content-farm good — actually good. People writing honestly about the thing that broke at 3am, the assumption that quietly rotted, the fix they were embarrassed they'd missed. I'd come for a translation and I'd leave with an idea lodged in my head that had nothing to do with the words. At some point — I don't remember deciding it — I stopped asking my AI to just translate the post, and started asking it something else: "Is there anything in here we should actually be using?" That question changed what the tool was. A translator turns one language into another. What I'd started doing was turning someone else's hard-won lesson into a change in my own system — and the AI wasn't a dictionary for that job. It was the thing that read the post, understood my setup, found the overlap, and then — the part that still surprises me — built it and tested it. That's the theft this series is named for. Not the words. The lessons. From translator to research partner, in three steps Looking back, the tool climbed through three jobs, and I

AI is moving fast, and it feels like there's a new concept to learn every week. In an effort to actually understand this whole new world instead of just skimming past it, I've been writing ELI5 articles breaking down concepts that show up constantly in AI conversations but rarely get explained simply. This time, a term that gets thrown around a lot without much explanation: the context window. AI 101 Recap The context window is the total number of input and output tokens an LLM can consider while generating a response. Your prompt, the conversation history, and even the model's response all share that same "budget" of tokens. As a conversation with an LLM grows longer, more tokens live in this window. So far so good. Every AI model has a limit on how many tokens it can hold in its "working memory" at once. So the interesting part with the context window is what happens when you reach these limits. Why are there limits? There are several reasons models have context window limits. Processing more tokens requires more memory and computation, making every request slower and more expensive. On top of that, today's models struggle to use very long contexts effectively. They naturally pay more attention to the beginning and end of a conversation than the middle ("lost in the middle" problem). The Amnesia Problem An AI model has no persistent memory between conversations. Within a long conversation, it only sees whatever still fits inside its context window. Think of it as a sliding window: as new messages come in, older ones eventually slide out and are no longer visible to the model. This is why a long conversation can feel like the model has "forgotten" something you told it early on. It doesn't actually forget, it just no longer has access to that part of the conversation, unless the product you're using has built something extra on top to handle it. How RAG helps RAG (retrieval-augmented generation) sounds technical, but the idea is simple: look it up before you answer

🚀 JavaScript Fundamentals (Week-03): Understanding the Concepts That Every Developer Should Know "Writing JavaScript code is one thing, but understanding what happens behind the scenes is what makes you a better developer." When I first started learning JavaScript, I knew how to declare variables and write functions. However, I often found myself asking questions like: Why are there three ways to declare variables? What exactly is hoisting? How does JavaScript execute my code? Why can an inner function access variables from its parent function? What does the this keyword actually refer to? Why do developers keep talking about writing clean code? This week, I focused on understanding these core JavaScript concepts instead of simply memorizing syntax. In this article, I'll explain each concept in a beginner-friendly way with examples and practical explanations. 📚 Topics Covered Variables ( var , let , const ) Hoisting Lexical Scope Execution Context Call Stack Closures this Binding DRY Principle KISS Principle Let's start from the beginning. 📦 Variables in JavaScript What is a Variable? A variable is a named container used to store data in memory . Instead of writing the same value repeatedly, we store it inside a variable and reuse it whenever required. For example, let name = " Sai " ; console . log ( name ); Output Sai Here, let → Variable declaration keyword name → Variable name "Sai" → Stored value Why Do We Need Variables? Imagine writing this: console . log ( " Sai " ); console . log ( " Sai " ); console . log ( " Sai " ); If the value changes, every occurrence must be updated. Using variables, let name = " Sai " ; console . log ( name ); console . log ( name ); console . log ( name ); Now changing one line updates every usage. Variables improve: Readability Reusability Maintainability Types of Variables JavaScript provides three ways to declare variables. var let const Although all three create variables, they behave differently. var var was introduced in the

I'm AlanWu. I'm in junior high. I've written a lot of bad code. Here's what I changed to make it less bad. 1. Name things like a human // Don't do this int d ; // days? distance? damage? int cnt = 0 ; // "cnt" — you know, the classic vector < int > v ; // v of what // Do this int daysUntilDeadline ; int errorCount = 0 ; vector < int > studentScores ; Full words, no abbreviations. idx instead of i in loops is fine. But sz for size, cnt for count, ptr for pointer — just type the word. You're not being charged by the character. 2. Functions should do one thing If you need the word "and" to describe a function, split it. // Bad: does two things, name lies void loadAndValidateConfig () { readFile (); checkSyntax (); } // Better Config loadConfig ( string path ) { return parseConfig ( readFile ( path )); } bool validateConfig ( const Config & cfg ) { return cfg . width > 0 && cfg . height > 0 ; } My rule of thumb: if a function is longer than what fits on one screen, break it. If I can't describe what it does in one sentence without "and", break it. 3. Comments explain WHY, not WHAT // Bad — tells me what the code already says // Loop through all students for ( auto & s : students ) { s . score += 5 ; } // Good — tells me WHY, which the code can't // Extra credit: 5 points for submitting early for ( auto & s : students ) { s . score += 5 ; } If you're writing a comment that just restates the next line of code, delete it. The only comments worth keeping are the ones that answer "why did I do it this way?" 4. Don't nest too deep // Bad — 3 levels deep, I've already forgotten what the top level was for ( auto & student : students ) { if ( student . hasSubmitted ()) { for ( auto & answer : student . answers ) { if ( answer . isCorrect ()) { score ++ ; } } } } // Better — flatten with early exits for ( auto & student : students ) { if ( ! student . hasSubmitted ()) continue ; for ( auto & answer : student . answers ) { if ( ! answer . isCorrect ()) continue ; score ++ ; } } Al

I've built a lot of voice integrations. Every single one needed a deployment whose only job was to talk to the Sinch API: receive the callback, translate it into SVAML or a Conversation API call, hand off to the rest of the application. Not the interesting part. Just the piece that has to exist because your code and Sinch's network live in different places, with a round trip between them on every call event. Sinch Functions moves that piece into the network itself. Your voice and messaging handlers run on the same infrastructure that's already carrying your calls and messages, right where the callbacks originate. This isn't a general-purpose Lambda replacement: the rest of your application, and any compute that isn't glue against Sinch's APIs, stays exactly where it is, whether that's AWS, Azure, or your own infrastructure. Your order lookup, your database writes, your actual business logic: still on Lambda or wherever you already have it. Functions is specifically for the code that exists only to bridge your app and the Sinch network, not a place to run your whole system. I've been trying it out and this post walks through getting set up, writing a basic voice function, and deploying it. Pricing is usage-based and separate from your Voice and Conversation usage: $0.10 per compute-hour (first hour free each month), $0.05 per GB-month of storage (first 0.1 GB free), $0.05 to $0.15 per GB-month for the database depending on tier (first 0.1 GB free), and $5.00 per month per function if you want it kept always-on instead of scaling to zero. These are the current Standard rates from your project's Billing Overview in the Sinch dashboard; treat them as a snapshot, not a guarantee, given the Alpha status below. Sinch Functions is listed as Alpha in the Sinch Build dashboard. Expect the CLI, runtime APIs, pricing, and this walkthrough itself to change before general availability. Treat it as something to experiment with, not something to put in front of production traffic y

For a long time, I believed coding was only for people who studied computer science or worked as professional developers. Whenever I saw a screen filled with code, it looked like a completely different language. There were brackets, symbols, functions, and terms I did not understand. I assumed learning it would require years of study before I could create anything useful. That changed when I encountered a repetitive task at work. I was regularly copying information from a spreadsheet, checking each row, preparing an email, sending it, and updating the status manually. The work was manageable, but completing the same process repeatedly took time and left room for mistakes. I started wondering if the spreadsheet could do some of the work for me. That question led me to Google Apps Script. At first, I did not even know where to begin. I understood the result I wanted, but I did not know how to translate it into code. I could explain the process clearly to another person, but explaining it to a computer felt different. AI became my starting point. I described the task and asked it to create a script. Within seconds, it gave me several lines of code. I copied them, ran the script, and immediately received an error. My first reaction was frustration. I had expected the code to work because it looked complete. But I soon realized that generated code was not automatically working code. I went back and explained the error. AI suggested a change, so I tested it again. Another issue appeared. I repeated the process until the automation finally worked. The moment it worked, something changed in the way I viewed coding. I did not suddenly become a programmer, but I had created something useful. A task that previously required several manual steps could now happen automatically. I became curious about what else I could build. I started experimenting with confirmation emails, timestamps, form submissions, missing-data checks, and automatic reports. Each project introduced me to a

🚀 JavaScript Fundamentals (Week-03): Building a Strong Foundation "Before learning frameworks like React or backend technologies like Node.js, it's essential to build a strong understanding of JavaScript fundamentals. A solid foundation makes advanced concepts much easier to learn." Introduction During Week-03 of my Full Stack Development learning journey, I focused on understanding the fundamental concepts of JavaScript . Instead of only writing code, I wanted to understand how JavaScript works behind the scenes . In this week, I learned about variables, hoisting, different types of scope, execution context, call stack, closures, the this keyword, call() , apply() , bind() , module patterns, and clean coding principles like DRY and KISS . In this blog, I'll explain each concept in a simple and beginner-friendly way with examples. 📚 Topics Covered What is JavaScript? Variables ( var , let , const ) Hoisting Scope Global Scope Function Scope Block Scope Lexical Scope Scope Chain Execution Context Call Stack The this Keyword call() , apply() , and bind() Closures Module Pattern Common var vs let Bugs DRY Principle KISS Principle Conclusion 📌 What is JavaScript? JavaScript is a high-level, interpreted, single-threaded programming language used to build interactive and dynamic web applications. Initially, JavaScript was designed to run only in web browsers, but today it can also run on servers using Node.js . Some common uses of JavaScript include: Creating interactive web pages Form validation DOM manipulation API communication Web application development Backend development with Node.js Example console . log ( " Hello, JavaScript! " ); Output Hello , JavaScript ! 📦 Variables Variables are containers used to store data. JavaScript provides three ways to declare variables: var let const var Characteristics Function Scoped Can be redeclared Can be reassigned Hoisted var name = " Sai " ; var name = " Rahul " ; console . log ( name ); Output Rahul let Characteristics Block

A simple tutorial series on go in Hinglish. Jitna mujhe aata hai utna, aur zyada tar mere notes se! Note: Me non-native speaker hu to spelling mistakes to honge, is liye Hinglish spellings aur grammar ke liye main AI use karunga, par dev ke bot ko pata nahi chalega kyuki ye English nahi hai 😉 Parichay / Intro Shuruat hum isse karenge ki Go kya hai aur uske fayde kya hain. Pehle hum Wikipedia ki definition dekhte hain: To, Go ek aasan language hai. Go compiled language hai, matlab ek bar compiler ko humne apna code diya to wo ek executable file dega jo sidha hum chala sakte hain bina kisi aur dependency ke, jaise ki Python ka interpreter. Dusri high-level languages jaise Python ya JavaScript se Go tez chalta hai. Garbage collected hai, yani C ki tarah hame memory ko manually manage karna nahi padega. Go ka istemal kahan hota hai? APIs aur Web Servers banane me Network Programming aur Distributed Systems me Cloud-Native Applications aur Microservices banane me DevOps aur Infrastructure Automation me Command Line (CLI) Tools banane me Agar upar ki baatein abhi samajh na aayein, to koi baat nahi. Filhal itna samajh lijiye ki Go ka istemal bahut jagah hota hai to job ke liye kaam aayega. To ye thi Go ki kahani, CSM ki zubani... (jo chalti rahegi!) Aur haan, har post ke aakhir me meri ek shayari hogi, jo aapko guru dakshina ke roop me jhelni padegi! 😄 ख़यालों को बातों में उलझाए रखना । इस पल के हक़ीक़त को सुलझाए रखना । शिद्दत से चाहा जो मिल कर रहेगा । चेहरे पे मुस्कान थोड़ी बनाए रखना ।। -csm

Every time you run a JavaScript program, a lot happens behind the scenes. Variables are allocated memory, execution contexts are created, functions are pushed onto the call stack, and the engine starts executing your code. But before we dive into all of that, let's first understand what JavaScript actually is and why it was created. An Introduction to JavaScript What is JavaScript? JavaScript is a programming language that was originally created in 1995 by Brendan Eich in just 10 days while he was working at Netscape. JavaScript is a high-level programming language primarily used to make web pages interactive. Today, it is also used to build servers, mobile applications, desktop software, and much more. Why was JavaScript created? JavaScript was created to make web pages alive . But what does "alive" mean? it means adding interactivity (e.g., animations, clickable buttons, popup menus, etc.) to the static web pages. Today, JavaScript isn't limited to browsers. With runtimes like Node.js, it can also be used to build backend applications and APIs, which allow you to add more functionality to a website. Did you know? When JavaScript was created, it initially had another name: “LiveScript”. Where can JavaScript be used? In your browser — every interactive website uses it (Facebook, YouTube, Gmail). On servers — through Node.js, you can build backend APIs. In mobile apps — using frameworks like React Native. In desktop apps — VS Code itself is built using JavaScript (Electron). In smart devices, games, robots, and much more. Now that we know what JavaScript is, another question comes to mind: How does JavaScript execute my code? Before answering that, let's first understand Who executes my code? . The answer is: The JavaScript Engine The JavaScript Engine We already know what JavaScript is, but what exactly is this engine ? The "Engine" A JavaScript engine is a piece of software responsible for executing JavaScript code. Every environment that runs JavaScript, whether i

Introduction A callback function is one of the most important concepts in JavaScript. It allows one function to execute another function after completing a task. Callback functions are widely used in JavaScript for handling asynchronous operations such as API requests, file reading, event handling, and timers. What is a Callback Function? A callback function is a function that is passed as an argument to another function and is executed later. In simple words: A callback is a function that is called after another function finishes its work. Syntax function greeting () { console . log ( " Good Morning! " ); } function welcome ( callback ) { console . log ( " Welcome! " ); callback (); } welcome ( greeting ); Output Welcome! Good Morning! Explanation greeting() is the callback function. welcome() accepts a function as a parameter. callback() executes the greeting function after printing "Welcome!". Real-Life Example Imagine you order food at a restaurant. You place the order. The chef prepares the food. After the food is ready, the waiter serves it. Here, serving the food happens only after preparation is complete. This is exactly how callback functions work. Example 1: Email Sending function emailSent () { console . log ( " Email Sent Successfully! " ); } function sendEmail ( callback ) { console . log ( " Sending Email... " ); callback (); } sendEmail ( emailSent ); Output Sending Email... Email Sent Successfully! Example 2: Download File function downloadComplete () { console . log ( " Download Complete! " ); } function downloadFile ( callback ) { console . log ( " Downloading File... " ); callback (); } downloadFile ( downloadComplete ); Output Downloading File... Download Complete! Why Do We Use Callback Functions? Callback functions are useful because they: Execute code only after another task finishes. Improve code reusability. Handle asynchronous operations. Make event handling easier. Help avoid repeating code. Where Are Callback Functions Used? Some common u

Scan a menu, pay a bill, onboard a smart plug, and you are using a piece of technology that was never meant for any of those things. The QR code was invented in 1994, and its original job was tracking car parts on a factory floor. Understanding why it was built the way it was explains why it now shows up on nearly every connected device. Who invented the QR code The QR code was created in 1994 by a team led by engineer Masahiro Hara at Denso Wave, a subsidiary of the Toyota group in Japan. At the time, the automotive industry ran on standard one-dimensional barcodes, the striped labels still seen on grocery products. Those barcodes held very little data, usually around 20 characters, and a busy assembly line often needed a worker to scan ten different labels on a single box of components. It was slow, and it was error-prone. Hara wanted a code that could store far more information and be read much faster. His answer was to go two-dimensional: instead of encoding data only in the width of vertical bars, a QR code (short for "Quick Response") stores data across a grid of black and white squares, packing in thousands of characters in a fraction of the footprint. The board game that shaped it The most famous detail of the QR code's origin is where Hara found his design inspiration. He was reportedly playing the board game Go on a lunch break, staring at the black and white stones arranged on the grid, when the idea of encoding information in a two-dimensional matrix of light and dark cells clicked into place. The harder problem was speed. A scanner needs to find the code and figure out its orientation before it can read anything, and in a factory a label might be rotated any which way. Hara's team solved this with the three distinctive square markers in the corners of every QR code. Those "position detection patterns" use a ratio of black to white areas that almost never occurs by chance in printed material, so a scanner can instantly locate the code and work out its an