Callback function in JavaScript || JS Interview Questions 2025 #coding #shorts

🔥 Spot the Bug – JavaScript Function Edition


console.log(add(2, 3));

var add = function(a, b) {
return a + b;
};

Looks harmless? Think again 😬
This one-liner fails at runtime with:


❌ TypeError: add is not a function
But why?

💡 Here's the trick:

When you use a function expression with var, only the variable gets hoisted, not the function definition. So at the time of the console.log, add is just undefined — not a function!

✅ Correct Version (Function Declaration):


function add(a, b) {
return a + b;
}

console.log(add(2, 3)); // ✅ 5

✅ OR Fix the Timing (Function Expression):


var add = function(a, b) {
return a + b;
};

console.log(add(2, 3)); // ✅ 5

🧠 Understanding hoisting in JS is critical to avoid subtle bugs like this!

💬 Drop a 🧠 if you learned something new!
🔁 Share with your coding buddy who's still learning functions!
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