javascript: July 2025

1.Hoisting:

-----------2-----------2-----------2-----------2-----------2-----------2-----------2-----------2-----------2--------

🔹 Using var:

var is function scoped, so inside the loop, each iteration shares the same i
setTimeout is asynchronous, so the loop finishes before any of the callbacks run
By the time the callbacks execute, i is already 3
That’s why 3 is printed three times

🔹 Using let:

let is block scoped, meaning each loop iteration creates a fresh binding of i
Each setTimeout captures the current value of i
So it prints 0, 1, 2 — as expected

“var behaves differently from let, as it doesn't create a new variable for each loop iteration.”

var i is function-scoped

Output: You might expect it to log: 0, 1, 2

But instead, it prints: 3, 3, 3With let, each iteration gets a new block-scoped i

Output:

So each arrow function captures a distinct copy of i (0, then 1, then 2)

Why 3 Output instead 2:

iteration 1: callback delays at this time i =0,
iteration 2: callback delays at this time i =1
iteration 3: callback scheduled at this time i =2 and executed after this so it is iterated again 3

FINAL:

-------3--------3-----------3------------3---------3-------------3-------------3------------3----------

📘 console.log()

Purpose: General-purpose logging
Usage: For debugging, tracking values, or displaying routine messages

console.warn()

Purpose: Signals a warning or potential issue
Usage: Highlight deprecated code, suspect logic, or cautionary flags

--------4----------4---------4------------4----------4----------4-----------4-

-------5-------5----------5----------5----------5

----6-----6----6--------6-----------6------------6-------------6----------6----------6-------6----

1.Allocation to same memory and 2. Allocation to different memory with object.assign

Both c and d point to the same object in memory, which means any change to one reflects in the other.
You're not copying the contents of c into d. You're just copying the reference

Want to explore how to break that shared reference and create a copy instead? You can do it with spread syntax, Object.assign(), or deep cloning techniques. Say the word!