Loops

Loops allow you to repeat a block of code multiple times. They are essential for automating repetitive tasks and processing collections of data.

1. Why Loops? 🔄

What is it? A control structure that repeats code until a specified condition is met.

Why use it? Imagine you need to print numbers from 1 to 100. Writing console.log(1), console.log(2)... is tedious. Loops do this in 3 lines.

How it works:

1. Initialize a counter.
2. Check a condition.
3. Run the code.
4. Update the counter.
5. Repeat until condition is false.

2. The for Loop 🎯

Best for: When you know exactly how many times you want to loop.

Syntax: for (initialization; condition; increment)

3. The while Loop 🔁

Best for: When you don't know how many times to loop (e.g., "keep asking until user enters correct password").

Syntax: while (condition) { ... }

4. The do...while Loop 🔄

Best for: When you need the code to run at least once, regardless of the condition.

Syntax: do { ... } while (condition);

5. Modern Loops: for...of & for...in 🎨

ES6 introduced cleaner ways to loop through data.

for...of (Iterables)

Best for: Arrays, Strings, NodeLists. It gives you the values.

for...in (Objects)

Best for: Objects. It gives you the keys (property names).

6. Controlling Loops: break & continue 🛑

• break: Exits the loop immediately.
• continue: Skips the current iteration and moves to the next one.

Practical Example: Data Processor 📊

Quiz

Key Takeaways

✅ for: Standard loop, good for counting.
✅ while: Good when iteration count is unknown.
✅ for...of: Best for Arrays (Values).
✅ for...in: Best for Objects (Keys).
✅ break / continue: Control flow within loops.

What's Next?

Now that you can repeat code, let's learn how to organize it into reusable blocks with Functions!

Keep coding! 🚀