Conditionals

Conditionals allow your code to make decisions. Without them, code would just run from top to bottom. With them, your program becomes intelligent!

1. The if Statement 🤔

What is it? The most basic form of decision making. It executes a block of code only if a specified condition is true.

How it works: if (condition) { // do something }

2. The switch Statement 🔀

What is it? A cleaner way to compare a single value against multiple options.

Why use it? When you have many else if checks on the same variable, switch is more readable.

Crucial: Don't forget the break keyword! Without it, code "falls through" to the next case.

3. Truthy and Falsy Values 🎭

In JavaScript, values aren't just true or false. Every value can be treated as true or false in a conditional.

Falsy Values (Evaluate to false):

1. false
2. 0 (and -0, 0n)
3. "" (Empty string)
4. null
5. undefined
6. NaN

Truthy Values (Evaluate to true):

• Everything else!
• "0" (String containing zero)
• "false" (String containing "false")
• [] (Empty array)
• {} (Empty object)

4. Ternary Operator ❓

What is it? A shorthand for if...else that fits on one line.

Syntax: condition ? valueIfTrue : valueIfFalse

Best Practice: Use it for simple assignments. Avoid nesting them (it gets hard to read).

5. Logical Operators in Conditionals 🧠

You can combine conditions using && (AND), || (OR), and ! (NOT).

Practical Example: Access Control System 🔐

Quiz

Key Takeaways

✅ if/else is for general logic.
✅ switch is for checking one variable against many values.
✅ Truthy/Falsy: Learn the 6 falsy values (false, 0, "", null, undefined, NaN).
✅ Ternary (? :) is great for simple assignments.
✅ Short-circuiting (&&, ||) is a powerful pattern.

What's Next?

Now that you can make decisions, let's learn how to repeat actions with Loops!

Keep coding! 🚀