How JavaScript Works: The Runtime Environment

How JavaScript Works: The Runtime Environment A program is fundamentally about two things: Allocating Memory: Where do we store our data and variables? Parsing and Executing: How do we read and run our instructions? To run our JavaScript code, we need an engine that translates it into machine code. Browsers have different engines, like V8 in Chrome and SpiderMonkey in Firefox. For server-side execution, we use environments like Node.js, which is built on the V8 engine. The JS Engine is the "heart" where your code is actually understood and executed. Inside the engine, we have two key parts: Memory Heap: This is where memory allocation happens. When you create variables, objects, or functions, they get allocated space in the heap. This is why we need to be mindful of memory leaks. For example, by avoiding unnecessary global variables that never get cleared. Call Stack: This is where your code is read and executed, line by line. It's a stack data structure that records where we are in the program. Each function call is pushed onto https://lnkd.in/gX--SZ-p

package.json In the Node.js and JavaScript ecosystem, the package.json file is much more than a simple configuration file. It acts as the manifest for your project, holding essential metadata, dependencies, scripts, and more. A deep understanding of package.json empowers you to optimize your development workflow, streamline deployments, and maintain consistency across various environments. This guide dives into every aspect of package.json from basic metadata to advanced configurations providing practical insights and best practices to help you master this critical file. The package.json file is a JSON-formatted document that serves as the heart of your Node.js project. It provides: Project Metadata: Information like project name, version, description, author, and license. Dependencies: A list of packages your project needs to run, divided into production (dependencies) and development (devDependencies). Scripts: Custom commands for automating tasks such as starting your server, running tests, or b https://lnkd.in/gRsY8Wgk

V8 engine in Node.js Source website: geeksforgeeks.org "The V8 engine is an open-source JavaScript Engine developed by Google. It is primarily designed to execute JavaScript code. V8 is used in multiple applications, especially in Google Chrome, but later utilized to create Node.js for server-side coding. V8 compiles JavaScript directly to machine code rather than using an interpreter. This compilation process allows for the efficient execution of JavaScript, which is key to the performance benefits in both web browsers (like Chrome) and Node.js applications." Source link: https://lnkd.in/g3UW3EBq More Relevant Sources: ( medium.com ) https://lnkd.in/g2bemyms

Did you know that Validator.js, the popular Javascript library can also be used to sanitize (clean/format) your inputs? So, I have been using validator for quite a while now. I mainly used it for, well, validating my inputs. Little did I know, You can also use it for sanitizing your data with methods such as: 1. .blacklist(): You can use this to remove selective characters from your data. 2. .whitelist(): You can use this to remove everything but your selective characters from your data. 3. .escape(): You can use this to automatically sanitize html code. It looks for potentially harmful content and then changes (escapes) those characters to their HTML entity counter-parts. (this one is my favorite) You can read the full docs for this library at: https://lnkd.in/dGaPXpBq Or you can quickly install it in your project via: `npm i validator` --- Bonus Question: What did you learn today?

💻 JavaScript Variables: The Building Blocks of Logic 🧩 In JavaScript, everything begins with a variable — the foundation of data handling and logic. Variables make your code dynamic, reusable, and readable. Let’s explore them clearly 👇 🧠 1️⃣ What Are Variables? A variable is like a container that holds data values — strings, numbers, arrays, or objects. let language = "JavaScript"; const version = "ES6"; var oldSyntax = "Still works, but not preferred"; 💡 2️⃣ Types of Variables (Simple View) 🔸 var → Function-scoped, old syntax, avoid in modern code. 🔸 let → Block-scoped, used when values can change. 🔸 const → Block-scoped, used when values must stay constant. 💬 “Scope” means where your variable can be accessed. ⚡ 3️⃣ Why Modern JS Uses let and const ✅ Prevents accidental overwrites ✅ Improves code readability ✅ Avoids scope-related bugs ✅ Works perfectly with ES6 features (arrow functions, modules, etc.) ✨ Takeaway “Use const by default. Switch to let only when your value must change. Avoid var — it belongs to JavaScript’s past.” #JavaScript #CodingTips #WebDevelopment #Frontend #ES6 #DeveloperLife

JavaScript — Pass by Reference and Pass by Value (Made Simple) If you ever changed one variable and somehow another one also changed — Pass by Value and Pass by Reference. Let’s understand both of them clearly with small examples. Primitive types in JavaScript are — string, number, boolean, bigint, null, and undefined. These are simple. When you assign or pass them, copy of the actual value and allocates separate memory pointing to a new address. let a = 12; let b = a; b = 13; console.log(b, a); // 13, 12 👉 a and b are two different boxes. Primitive = always copied by value Now let’s discuss about Non-Primitive types. Now this is where confusion starts. reference (memory address) where the value is stored. So when you assign one object or array to another variable, That’s why when you change one, the other also changes. const a = [1, 2, 3, 4, 5]; const b = a; b.pop(); console.log(b, a); // both will print the same - [1, 2, 3, 4] Here, both a and b point to the same array in memory. b, 🧩 Changing (mutating) means both get affected. But her https://lnkd.in/gFKiXCrE

JavaScript — Pass by Reference and Pass by Value (Made Simple) If you ever changed one variable and somehow another one also changed — Pass by Value and Pass by Reference. Let’s understand both of them clearly with small examples. Primitive types in JavaScript are — string, number, boolean, bigint, null, and undefined. These are simple. When you assign or pass them, copy of the actual value and allocates separate memory pointing to a new address. let a = 12; let b = a; b = 13; console.log(b, a); // 13, 12 👉 a and b are two different boxes. Primitive = always copied by value Now let’s discuss about Non-Primitive types. Now this is where confusion starts. reference (memory address) where the value is stored. So when you assign one object or array to another variable, That’s why when you change one, the other also changes. const a = [1, 2, 3, 4, 5]; const b = a; b.pop(); console.log(b, a); // both will print the same - [1, 2, 3, 4] Here, both a and b point to the same array in memory. b, 🧩 Changing (mutating) means both get affected. But her https://lnkd.in/gFKiXCrE

🚀 Understanding var, let, and const in JavaScript In JavaScript, we use var, let, and const to declare variables — but they behave differently. Knowing when to use which one can make your code cleaner and bug-free. 👇 🔹 var Introduced in ES5 (older way). Function-scoped — accessible within the entire function where it’s declared. Can be redeclared and reassigned. Hoisted to the top of its scope (but initialized as undefined). var name = "Abdul"; var name = "Hak"; // ✅ Redeclaration allowed console.log(name); // Output: Hak 🔹 let Introduced in ES6 (2015). Block-scoped — only accessible inside { } where it’s defined. Can be reassigned but not redeclared within the same scope. Hoisted but not initialized (accessing before declaration gives an error). let age = 25; age = 26; // ✅ Allowed // let age = 27; ❌ Not allowed console.log(age); 🔹 const Also introduced in ES6. Block-scoped like let. Cannot be reassigned or redeclared. Must be initialized at the time of declaration. const country = "India"; // country = "USA"; ❌ Not allowed console.log(country); 💡 Pro Tip: Use let and const instead of var in modern JavaScript — they make your code safer and more predictable. #JavaScript #WebDevelopment #Coding #LearnToCode #FrontendDevelopment