#javascript Interview question: 79. What is CORS ? (Most asked) CORS means cross origin resource sharing. It is a security feature that allows the webapplications from one domain to request the resources like Api’s/scripts from another domain. cors works by adding specific http headers to control which origins have access to the resources and under what conditions. Learn 232 interview ques & ans for free on interviewdepth.com #javascript #javascriptdeveloper #reactjs #reactnative #vuejsdeveloper #angular #angulardeveloper
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This tiny newline can break your JavaScript code😱 #coding #javascript #frontend This JavaScript short explains one of the most confusing return statement bugs caused by Automatic Semicolon Insertion (ASI). Learn why the same-looking functions return different results — and how to avoid this hidden trap in your code. Perfect for JavaScript interviews, beginners, and advanced devs who want to understand JS deeply. #JavaScript #CodingShorts #JSInterview #TheDeveloperSchool #JavaScript #CodingShorts #TheDeveloperSchool #WebDevelopment #JSInterview #FrontendDeveloper #FullStackDeveloper #JavaScriptTips #LearnCoding #CodeShorts #ProgrammingShorts #TechInterview
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Is Node.js single-threaded or multi-threaded? This is one of the most frequently asked questions in Node.js interviews, and the best way to answer it is to understand what happens behind the scenes. To explain this, you should first know the basics of • The JavaScript Engine • libuv • The Event Loop • The Thread Pool 💡So what is the right answer? Node.js is both single-threaded and multi-threaded, depending on the situation. JavaScript execution in Node.js runs on a single main thread, which handles synchronous code. However, when asynchronous operations occur (such as filesystem operations, network requests, hashing, compression), Node.js uses libuv’s thread pool, which provides multiple threads to handle those tasks in the background. So • Synchronous code → behaves as single-threaded • Asynchronous tasks → handled through a multi-threaded thread pool 💡Thread Pool By default, Node.js provides 4 threads in the thread pool. You can increase this number based on your workload by using "process.env.UV_THREADPOOL_SIZE" When a callback is triggered, the task occupies one thread. After completion, the thread becomes available again. If all threads are busy and a new request arrives, that request must wait until a thread is free. This is how the thread pool manages async work inside Node.js. Understanding this internal flow gives you a clear and confident answer in interviews. Just keep learning and exploring how things really work inside. 🙏 Special Mention The man who made me fall in love with Node.js is Akshay Saini 🚀 I absolutely love the way he explains concepts. Truly amazing. Thank you so much sir for sharing such great knowledge. #NodeJS #JavaScript #Backend #SystemDesign #EventLoop #ThreadPool #LearningEveryday #WebDevelopment
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💡 JavaScript Interview Insight What gets hoisted: variables or functions? 🤔 ✅ Both! But not in the same way 👇 Function declarations are fully hoisted — you can call them before they’re defined. Variables declared with var are hoisted too, but only the declaration, not the value (they’re initialized as undefined). let and const are hoisted but remain in the Temporal Dead Zone, so you can’t access them before declaration. 🧠 Tip: Understand hoisting to avoid those “undefined” bugs! #JavaScript #FrontendDevelopment #CodingTips
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JavaScript interview Questions #day3rd Loops & Conditions Q1: What are the different types of loops in JavaScript? for loop: Traditional loop with initialization, condition, and increment while loop: Executes while condition is true, checks condition before execution do-while loop: Executes at least once, checks condition after execution for...in: Iterates over enumerable properties of objects for...of: Iterates over iterable values (arrays, strings, etc.) Q2: How does for...in differ from for...of? for...in: Iterates over enumerable property keys (including prototype chain), best for objects for...of: Iterates over iterable values (arrays, strings, maps, sets), doesn't work with plain objects Q3: What is the difference between switch and if-else statements? if-else: Better for range comparisons, complex conditions, boolean checks switch: Better for exact value matching, more readable for multiple discrete values, uses strict comparison Q4: Explain break and continue statements break: Completely terminates the loop or switch statement continue: Skips the current iteration and continues with the next iteration of the loop Q5: What is short-circuit evaluation in JavaScript? Using logical operators (&&, ||) for conditional execution: a && b: Returns a if falsy, otherwise returns b a || b: Returns a if truthy, otherwise returns b Commonly used for default values and conditional execution #javascript #js #interview #questions #topquestions #javascriptinterview #100dayschallange #day3rd #3rdday #learningjavascript #learnjs #learnjavascript #howtoprefaireforjavascriptinterview #daythree
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🔥 JavaScript Interview Series(15): Inside the JavaScript Engine: V8 & SpiderMonkey Explained When preparing for advanced JavaScript interviews, understanding how JavaScript engines like V8 (used in Chrome and Node.js) and SpiderMonkey (used in Firefox) work internally can set you apart from average developers. These engines do more than just interpret JavaScript — they compile, optimize, and execute your code using complex architectures and Just-In-Time (JIT) compilation techniques. Let’s dive into 10 real interview questions that test your understanding of JavaScript internals, performance, and optimization strategies. Focus Area: Execution model, JIT compilation Standard Answer: interpreter executes code line-by-line, translating JavaScript directly into bytecode and running it immediately. This is fast for startup but slow for long-running applications. A JIT (Just-In-Time) compiler, on the other hand, compiles frequently executed code (hot paths) into optimized machine code while the program is running, improving performance over time. V8 and SpiderMonkey both use a hybrid https://lnkd.in/gTagtBc4
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🔥 JavaScript Interview Series(15): Inside the JavaScript Engine: V8 & SpiderMonkey Explained When preparing for advanced JavaScript interviews, understanding how JavaScript engines like V8 (used in Chrome and Node.js) and SpiderMonkey (used in Firefox) work internally can set you apart from average developers. These engines do more than just interpret JavaScript — they compile, optimize, and execute your code using complex architectures and Just-In-Time (JIT) compilation techniques. Let’s dive into 10 real interview questions that test your understanding of JavaScript internals, performance, and optimization strategies. Focus Area: Execution model, JIT compilation Standard Answer: interpreter executes code line-by-line, translating JavaScript directly into bytecode and running it immediately. This is fast for startup but slow for long-running applications. A JIT (Just-In-Time) compiler, on the other hand, compiles frequently executed code (hot paths) into optimized machine code while the program is running, improving performance over time. V8 and SpiderMonkey both use a hybrid https://lnkd.in/gTagtBc4
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⚡ 100 JavaScript Interview Questions – From Basics to Advanced 🚀 JavaScript is the most in-demand skill for web developers – and also the most asked in interviews. That’s why I’ve compiled 100 essential JavaScript interview questions you MUST revise before your next coding round. 📑 What’s covered: ✅ Basics – Variables, Data Types, Operators ✅ Functions, Scope & Closures ✅ Hoisting, this, Call/Apply/Bind ✅ Promises, Async/Await, Event Loop ✅ DOM Manipulation & Events ✅ ES6+ Features (Arrow Functions, Destructuring, Modules) ✅ Prototypes & Inheritance ✅ Error Handling ✅ Fetch, APIs & JSON ✅ Advanced Concepts – Currying, Debouncing, Throttling 💡 Perfect for placements, coding rounds, and professional #JavaScript #JS #Frontend #WebDevelopment #React #NodeJS #FullStack #Programming #InterviewPrep #CodingInterview #Placements #SoftwareEngineering #100DaysOfCode #StudyNotes #CheatSheet #LearnToCode #DevCommunity #CareerGrowth
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⚡ 100 JavaScript Interview Questions – From Basics to Advanced 🚀 JavaScript is the most in-demand skill for web developers – and also the most asked in interviews. That’s why I’ve compiled 100 essential JavaScript interview questions you MUST revise before your next coding round. 📑 What’s covered: ✅ Basics – Variables, Data Types, Operators ✅ Functions, Scope & Closures ✅ Hoisting, this, Call/Apply/Bind ✅ Promises, Async/Await, Event Loop ✅ DOM Manipulation & Events ✅ ES6+ Features (Arrow Functions, Destructuring, Modules) ✅ Prototypes & Inheritance ✅ Error Handling ✅ Fetch, APIs & JSON ✅ Advanced Concepts – Currying, Debouncing, Throttling 💡 Perfect for placements, coding rounds, and professional #JavaScript #JS #Frontend #WebDevelopment #React #NodeJS #FullStack #Programming #InterviewPrep #CodingInterview #Placements #SoftwareEngineering #100DaysOfCode #StudyNotes #CheatSheet #LearnToCode #DevCommunity #CareerGrowth
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⚡ 𝟭𝟬𝟬 𝗝𝗮𝘃𝗮𝗦𝗰𝗿𝗶𝗽𝘁 𝗜𝗻𝘁𝗲𝗿𝘃𝗶𝗲𝘄 𝗤𝘂𝗲𝘀𝘁𝗶𝗼𝗻𝘀 – 𝗙𝗿𝗼𝗺 𝗕𝗮𝘀𝗶𝗰𝘀 𝘁𝗼 𝗔𝗱𝘃𝗮𝗻𝗰𝗲𝗱 JavaScript is the most in-demand skill for web developers – and also one of the most frequently tested in interviews. That’s why I’ve compiled 100 essential JavaScript interview questions you MUST revise before your next coding round. 📑 𝗪𝗵𝗮𝘁’𝘀 𝗖𝗼𝘃𝗲𝗿𝗲𝗱: ✅ Basics – Variables, Data Types, Operators ✅ Functions, Scope & Closures ✅ Hoisting, this, Call/Apply/Bind ✅ Promises, Async/Await, Event Loop ✅ DOM Manipulation & Browser Events ✅ ES6+ Features (Arrow Functions, Destructuring, Modules) ✅ Prototypes & Inheritance ✅ Error Handling ✅ Fetch, APIs & JSON ✅ Advanced Concepts – Currying, Debouncing, Throttling 💡 𝑃𝑒𝑟𝑓𝑒𝑐𝑡 𝑓𝑜𝑟 𝑝𝑙𝑎𝑐𝑒𝑚𝑒𝑛𝑡𝑠, 𝑐𝑜𝑑𝑖𝑛𝑔 𝑖𝑛𝑡𝑒𝑟𝑣𝑖𝑒𝑤𝑠, 𝑓𝑟𝑜𝑛𝑡𝑒𝑛𝑑 𝑟𝑜𝑢𝑛𝑑𝑠, 𝑎𝑛𝑑 𝑝𝑟𝑜𝑓𝑒𝑠𝑠𝑖𝑜𝑛𝑎𝑙 𝑢𝑝𝑠𝑘𝑖𝑙𝑙𝑖𝑛𝑔. credit - ARUN DUBEY 📌 𝗥𝗲𝘀𝗼𝘂𝗿𝗰𝗲𝘀 𝘁𝗼 𝗔𝗰𝗰𝗲𝗹𝗲𝗿𝗮𝘁𝗲 𝗬𝗼𝘂𝗿 𝗙𝗿𝗼𝗻𝘁𝗲𝗻𝗱 𝗗𝗲𝘃𝗲𝗹𝗼𝗽𝗺𝗲𝗻𝘁 𝗝𝗼𝘂𝗿𝗻𝗲𝘆 📘 𝗖𝗮𝗿𝗲𝗲𝗿 𝗚𝘂𝗶𝗱𝗮𝗻𝗰𝗲 – 𝗙𝗿𝗼𝗻𝘁𝗲𝗻𝗱 𝗗𝗲𝘃𝗲𝗹𝗼𝗽𝗺𝗲𝗻𝘁 : https://lnkd.in/guhaEEQP 🎯 𝗕𝗼𝗼𝘀𝘁 𝗬𝗼𝘂𝗿 𝗟𝗶𝗻𝗸𝗲𝗱𝗜𝗻 𝗮𝗻𝗱 𝗡𝗮𝘂𝗸𝗿𝗶 𝗣𝗿𝗼𝗳𝗶𝗹𝗲: https://lnkd.in/gz4Uu8Ug 📕 𝗥𝗲𝘀𝘂𝗺𝗲 𝗥𝗲𝘃𝗶𝗲𝘄 𝗮𝗻𝗱 𝗢𝗽𝘁𝗶𝗺𝗶𝘇𝗮𝘁𝗶𝗼𝗻 https://lnkd.in/g3hkDm-J #JavaScript #JS #FrontendInterview #WebDevelopment #100DaysOfCode #LearnJavaScript #WebDeveloper #FrontendDeveloper
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