✅ JavaScript Interview Questions Answers 💼📜 1️⃣ Variables Q: What’s the difference between var, let, and const? A: • var is function-scoped and hoisted (can be redeclared). • let is block-scoped and cannot be redeclared in the same scope. • const is also block-scoped but must be initialized and cannot be reassigned. let x = 10; x = 20; // ✅ allowed const y = 5; y = 10; // ❌ Error: Assignment to constant variable 2️⃣ Functions Q: What are the different ways to define a function in JavaScript? A: • Function Declaration: function greet(name) { return Hello, ${name}; } • Function Expression: const greet = function(name) { return Hello, ${name}; }; • Arrow Function: const greet = name => Hello, ${name}; Q: What is the difference between a regular function and an arrow function? A: Arrow functions have a shorter syntax and do not bind their own this, making them ideal for callbacks. 3️⃣ Arrays Q: How do you iterate over an array in JavaScript? A: • Using for loop: for (let i = 0; i < arr.length; i++) { console.log(arr[i]); } • Using forEach: arr.forEach(item => console.log(item)); • Using map (returns a new array): const doubled = arr.map(x => x * 2); Q: How do you remove duplicates from an array? A: const unique = [...new Set(arr)]; 4️⃣ Loops Q: What are the different types of loops in JavaScript? A: • for loop • while loop • do...while loop • for...of (for arrays) • for...in (for objects) Q: What’s the difference between for...of and for...in? A: • for...of iterates over values (arrays, strings). • for...in iterates over keys (objects). 5️⃣ Conditionals Q: How does the if...else statement work in JavaScript? A: It executes code blocks based on boolean conditions. if (score >= 90) { console.log("A"); } else if (score >= 80) { console.log("B"); } else { console.log("C or below"); } Ternary Operator: let result = score >= 60 ? "Pass" : "Fail"; Q: What’s the difference between == and ===? A: • == compares values with type coercion. • === compares both value and type (strict equality). '5' == 5 // true '5' === 5 // false Bonus: Common Tricky Questions Q: What is hoisting in JavaScript? A: Hoisting is JavaScript’s behavior of moving declarations to the top of the scope. Only declarations are hoisted, not initializations. Q: What is the difference between null and undefined? A: • undefined: A variable declared but not assigned. • null: An intentional absence of value. 💬 Double Tap ♥️ For More
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