Petr Puzanov’s Post

🧠 A pattern I’ve started noticing in real-world projects: Code rarely breaks where it was written. It breaks where it was used differently than expected. Most bugs don’t come from complex logic — they come from mismatched assumptions. Things like: • A function expecting one shape of data • An API returning something slightly different • A component used in a way it wasn’t designed for • Edge cases nobody thought would actually happen And suddenly… everything looks correct, but something still fails. The more I work on production systems, the more I value: 📌 Explicit contracts over assumptions 📌 Clear inputs and outputs 📌 Defensive thinking around edge cases Because correctness isn’t just about writing logic. It’s about making sure that logic holds under real-world usage. Curious — what’s one bug you’ve seen that came from a wrong assumption? 👇 #SoftwareEngineering #Programming #WebDevelopment #CleanCode #Developers

I used to think I was being “efficient” by handling everything in one place. One class doing validation, business logic, API calls… even a bit of formatting on the side. It worked—until it didn’t. Debugging became a nightmare. Small changes broke unrelated things. Testing felt heavy. And onboarding new ideas into the code? Painful. That’s when I really understood the cost of ignoring the Single Responsibility Principle. When one piece of code tries to do too much, it becomes fragile. Hard to read. Harder to maintain. Lately, I’ve been focusing on doing less in each unit of code: * Smaller functions * Clear responsibilities * Better separation of concerns It’s not about being perfect—it’s about making the code easier for “future me” (and others). Still learning, still refactoring, but definitely seeing the difference. #SOLID

🧠 Quick Logic Test for Developers A small problem… but a common one in real applications. Let’s see how you solve it. 💻 Developer Challenge: Date Validation Create a rule/function that checks whether a given input date falls within the last 30 days (including today’s date). This type of logic is often used in: • Audit checks • Data filtering • Transaction validation • Reporting systems 🧪 Examples Input: 10 Feb 2026 Today: 09 Mar 2026 Output: TRUE Input: 01 Jan 2026 Today: 09 Mar 2026 Output: FALSE ⚡ Your Task Write a rule or function that: • Accepts a date as input • Checks if the date lies within the last 30 days • Returns TRUE or FALSE 👇 Comment your code below. Let’s see the different approaches developers take to solve this. #CodingChallenge #Programming #Developers #SoftwareEngineering #TechCommunity #CodingPractice #DeveloperCommunity #LearnToCode

💡 Rethinking Dependency Injection: Do We Always Need It? Dependency Injection (DI) is widely considered a best practice in modern software development. But does it need to be applied in every scenario? Consider transformation classes. 👉 If a transformation class is: - Used only once - Stateless - Not reused across components Injecting it as a service may not always be necessary. Creating an object directly at the point of use can often be a simpler and more practical approach. It helps keep the code: ✔️ Cleaner ✔️ Easier to read ✔️ Free from unnecessary abstraction DI is extremely valuable for managing shared dependencies, improving testability, and enabling loose coupling. However, overusing it can sometimes lead to avoidable complexity. ⚖️ The takeaway: Apply Dependency Injection where it truly adds value—not as a default for every class. Sometimes, simplicity is the better design choice. #SoftwareEngineering #CleanCode #Architecture #DependencyInjection #Programming #TechThoughts

𝐃𝐚𝐲 𝟏𝟎 𝐨𝐟 𝐀𝐥𝐠𝐨𝐫𝐢𝐭𝐡𝐦 𝐃𝐞𝐬𝐢𝐠𝐧 𝐚𝐧𝐝 𝐑𝐨𝐛𝐮𝐬𝐭 𝐂𝐨𝐝𝐞 𝐈𝐦𝐩𝐥𝐞𝐦𝐞𝐧𝐭𝐚𝐭𝐢𝐨𝐧 : 𝐓𝐞𝐬𝐭𝐢𝐧𝐠: 𝐔𝐧𝐢𝐭 𝐓𝐞𝐬𝐭𝐢𝐧𝐠 𝐚𝐧𝐝 𝐈𝐧𝐭𝐞𝐠𝐫𝐚𝐭𝐢𝐨𝐧 𝐓𝐞𝐬𝐭𝐢𝐧𝐠 𝐒𝐭𝐫𝐚𝐭𝐞𝐠𝐢𝐞𝐬 Let's talk testing! Specifically, the interplay between Unit and Integration testing when building robust algorithms. Unit tests verify individual components (functions, classes) in isolation. This ensures each piece works as expected before you assemble the puzzle. Integration tests, on the other hand, examine how these components work together. They catch issues that unit tests might miss, like incorrect data passing or unexpected interactions. Here's a less common perspective: consider property-based testing alongside unit tests. Instead of testing specific input/output pairs, you define properties that should always hold true, and the testing framework generates random inputs to verify these properties. This can uncover edge cases you might not think of manually! Striking the right balance between comprehensive unit testing and focused integration testing is key for robust code. It's an investment that pays off in maintainability and reliability. What's your go-to strategy for deciding what to unit test versus integration test? #SoftwareTesting #UnitTesting #IntegrationTesting #AlgorithmDesign #Coding #SoftwareDevelopment #RobustCode

Every shortcut you take today becomes someone's emergency at 2 am on a Friday. That someone is usually you. Technical debt is the interest paid on past decisions. Left unchecked, it doesn't just slow features; it drives good engineers out. Here are the 4 principles I use to eliminate it before it costs you: 1️⃣ Learn to smell the problem before it becomes one. Long methods, giant classes, switch statements everywhere, these aren't style issues. They're early warnings. If a function needs a comment to explain what it does, it needs a better name first. 2️⃣ Extract before it's too late. A 5-line block you can group is a function waiting to be born. The Extract Method is the most underused refactoring technique on every team I've seen. Small functions are easier to test, name, and delete. 3️⃣ Kill conditionals with polymorphism. A switch statement that grows with every new feature is a maintenance nightmare. Replace branching logic with proper abstractions. Your future self will thank you. 4️⃣ Refactor as a habit, not a sprint. Refactoring isn't a two-week cleanup ticket. It's a daily practice. "The Boy Scout Rule" applies perfectly: always leave the code better than you found it. The teams that ship fast aren't the ones who cut corners. They're the ones who pay back their debt before it compounds. Full breakdown 👇 https://lnkd.in/g2GkxP4D #Refactoring #TechnicalDebt #CleanCode #SoftwareEngineering #TypeScript #TechLead #EngineeringLeadership

One debugging practice almost nobody talks about: reviewing your code as different personas, not just a peer. Most debugging workflows look similar on the surface. What’s different here is the part we rarely talk about: how reviewing your own code through multiple personas exposes blind spots that normal peer review misses. I wrote a short piece about it: including the 7‑step workflow I use and the structural failures that usually hide underneath. Medium post: https://lnkd.in/gi8RHkga #SoftwareEngineering #Debugging #CodeReview #EngineeringLeadership #SoftwareArchitecture

I built a development framework for Claude Code and open-sourced it. The core process behind structured development is always the same: Analyze → Document → Plan → Approve → Test first → Build → Verify → Repeat So I turned that process into a reusable framework. No framework lock-in. No language lock-in. Just .claude/ files you can drop into any project. What’s inside: • A 12-step gated workflow from analysis to security scan • Hard approval gates - no code before plan approval • No exceptions 4 profiles, depending on the work: → porting: all 12 steps, with parity testing against legacy → greenfield: 11 steps, YAGNI-first → bugfix: 6 steps, regression test RED before fix → infra: 6 steps, with mandatory rollback docs Also included: • 7 skills loaded on demand for functional docs, workflows, parity checks, security scans, manuals, and end-to-end tests • 6 stack-agnostic agents that detect your framework and handle testing, documentation, legacy analysis, parity testing, API docs, and security scanning The core rule: No block of work ships until every active step is complete. Setup: cp -r claude-skills/.claude/ your-project/ cp CLAUDE.md.template your-project/CLAUDE(.md) Then set: active_profile: greenfield Pick a profile. Claude follows the process. This came out of real production work, then got extracted and generalized. Docs: https://lnkd.in/dhAdTD9e GitHub: https://lnkd.in/dTdbKY6F MIT licensed. Feedback welcome. #ClaudeCode #DeveloperTools #OpenSource #SoftwareEngineering #TDD

🚨 If your method has 8+ parameters… it’s not flexible — it’s fragile. It usually doesn’t start that way. We begin with 2–3 arguments. Then a new feature comes in, we add one more parameter. Another edge case appears, add one more. Before we know it, we're staring at a constructor or method with 10–15 arguments…and no one wants to touch it. This is how complexity quietly creeps into codebases. As a Senior Engineer, I've seen this pattern lead to: i) hard-to-read code ii) bugs due to incorrect argument order iii) painful refactoring Here are 3 ways to keep argument lists under control: 🔧 1. Prefer objects over primitives createUser(name, age, email, isActive, role) ❌ createUser({ name, age, email, isActive, role }) ✅ This improves readability and avoids order-related bugs. 🧩 2. Group related data into value objects If parameters belong together, they probably belong in a model/class. This makes your API cleaner and more expressive. 🔄 3. Refactor when arguments start growing A growing parameter list is a signal. Consider: i) splitting the method ii) using builder/factory patterns iii) rethinking responsibilities Good APIs are easy to use and hard to misuse. 💬 What's your rule of thumb — how many arguments are 'too many' for a method? #SoftwareEngineering #CleanCode #Programming #TechLeadership #DeveloperExperience

Code reviews aren't about finding mistakes; they are about shared ownership and quality. 🤝 While reviews can initially feel challenging, they are one of the most effective learning tools available. This updated guide goes beyond the basics to cover: 🚀 Detecting Performance Issues (N+1 queries, heavy renders) ✨ Improving Readability with Guard Clauses 🏗️ Architectural Review & Pattern Adherence 🛡️ Production Safety (Resilient async with Promise.allSettled) 🔗 Level up your reviews: https://lnkd.in/gWK9_BXM #CodeReview #Engineering #Teamwork #SoftwareQuality #DevCommunity