12 Scope in TypeScript

Description

🔍 TypeScript Essentials #12 Scope: Global, Function & Block-Level Mastery In this episode, we break down the concept of scope in TypeScript—how and where variables live, and why understanding their visibility is key to writing clean, maintainable code. From global declarations to block-level isolation, this tutorial helps you avoid common pitfalls and master variable control. 🎯 What You’ll Learn: - 🌍 Global Scope → Variables declared outside any function or block → Accessible anywhere in your codebase → Example: let globalVar = 'Available Everywhere'; - 🔧 Function Scope → Variables declared inside a function → Only accessible within that function → Example: function greet() { let message = 'Hello'; console.log(message); // ✅ } console.log(message); // ❌ Error - 📦 Block Scope (let & const) → Variables declared inside {} blocks (e.g., loops, conditionals) → Isolated to that block only → Example: if (true) { let status = 'Active'; console.log(status); // ✅ } console.log(status); // ❌ Error - 🧠 Why Scope Matters → Prevents variable collisions and unexpected behavior → Improves readability and debugging → Encourages modular, reusable code - ⚠️ Best Practices & Gotchas → Avoid var—it’s function-scoped and can lead to hoisting issues → Prefer let and const for predictable block-level behavior → Use meaningful variable names to reduce scope confusion 🧪 Real-World Use Cases: - Isolating loop counters and temporary flags - Managing state within functions and modules - Avoiding global pollution in large codebases - Writing safer automation scripts and test cases #typescript #Scope #VariableScope #TSBasics #FrontendDev #AutomationTesting #SDET #PlaywrightQA #TypeScriptTutorial #QAEngineering