## 🔹 Best Practices for Beginners
1. Use `const` by default, let when needed, avoid var
2. Always declare variables before use
3. Use strict equality (`===`) instead of ==
4. Name variables meaningfully (e.g., userAge not x)
5. Comment your code for complex logic

---

### 📌 What's Next?
In Part 2, we'll cover:
➡️ Conditionals (if/else, switch)
➡️ Loops (for, while)
➡️ Functions

#LearnJavaScript #CodingBasics #WebDevelopment 🚀

Practice Exercise:
1. Create variables for your name, age, and country
2. Calculate the area of a circle (PI * r²)
3. Try different type conversions

# 📚 JavaScript Tutorial - Part 2/10: Control Flow & Functions
#JavaScript #WebDev #Programming #Beginners

Welcome to Part 2 of our JavaScript series! Today we'll master decision-making and functions - the building blocks of programming logic.

---

## 🔹 Conditional Statements
Control program flow based on conditions.

### 1. if-else Statement

let age = 18;

if (age >= 18) {
    console.log("You're an adult");
} else {
    console.log("You're a minor");
}

### 2. Ternary Operator (Shorthand if-else)

let message = (age >= 18) ? "Adult" : "Minor";
console.log(message);

### 3. switch-case Statement

let day = 3;
let dayName;

switch(day) {
    case 1: dayName = "Monday"; break;
    case 2: dayName = "Tuesday"; break;
    case 3: dayName = "Wednesday"; break;
    default: dayName = "Unknown";
}

console.log(dayName); // "Wednesday"

---

## 🔹 Loops
Execute code repeatedly.

### 1. for Loop

for (let i = 1; i <= 5; i++) {
    console.log(`Count: ${i}`);
}
// Output: 1, 2, 3, 4, 5

### 2. while Loop

let count = 1;
while (count <= 5) {
    console.log(count);
    count++;
}

### 3. do-while Loop

let x = 1;
do {
    console.log(x);
    x++;
} while (x <= 5);

### 4. for...of Loop (Arrays)

const colors = ["red", "green", "blue"];
for (const color of colors) {
    console.log(color);
}

### 5. for...in Loop (Objects)

const person = {name: "Ali", age: 25};
for (const key in person) {
    console.log(`${key}: ${person[key]}`);
}

---

## 🔹 Functions
Reusable blocks of code.

### 1. Function Declaration

function greet(name) {
    return `Hello, ${name}!`;
}
console.log(greet("Ali")); // "Hello, Ali!"

### 2. Function Expression

const square = function(x) {
    return x * x;
};
console.log(square(5)); // 25

### 3. Arrow Functions (ES6+)

const add = (a, b) => a + b;
console.log(add(2, 3)); // 5

### 4. Default Parameters

function createUser(name, role = "user") {
    console.log(`${name} is a ${role}`);
}
createUser("Ali"); // "Ali is a user"

### 5. Rest Parameters

function sum(...numbers) {
    return numbers.reduce((total, num) => total + num, 0);
}
console.log(sum(1, 2, 3)); // 6

---

## 🔹 Practical Example: Grade Calculator

function calculateGrade(score) {
    if (score >= 90) return "A";
    else if (score >= 80) return "B";
    else if (score >= 70) return "C";
    else return "F";
}

const studentScore = 85;
console.log(`Grade: ${calculateGrade(studentScore)}`); // "Grade: B"

---

## 🔹 Scope in JavaScript
### 1. Global Scope

const globalVar = "I'm global";

function test() {
    console.log(globalVar); // Accessible
}

### 2. Function Scope (var)

function test() {
    var functionVar = "I'm function-scoped";
}
console.log(functionVar); // Error: Not accessible

### 3. Block Scope (let/const)

if (true) {
    let blockVar = "I'm block-scoped";
}
console.log(blockVar); // Error: Not accessible

---

## 🔹 Error Handling
### 1. try-catch-finally

try {
    // Risky code
    nonExistentFunction();
} catch (error) {
    console.log("Error occurred:", error.message);
} finally {
    console.log("This always executes");
}

### 2. Throwing Custom Errors

function divide(a, b) {
    if (b === 0) throw new Error("Cannot divide by zero!");
    return a / b;
}

---

## 🔹 Best Practices
1. Use strict equality (===) over ==
2. Prefer const/let over var
3. Keep functions small/single-purpose
4. Always handle errors
5. Use descriptive names for functions/variables

---

### 📌 What's Next?
In Part 3, we'll cover:
➡️ Arrays & Array Methods
➡️ Objects & JSON
➡️ Destructuring

#LearnJavaScript #CodingBasics #WebDevelopment 🚀

Practice Exercise:
1. Create a function to check if a number is even/odd
2. Write a loop that prints prime numbers up to 20
3. Make a temperature converter function (Celsius ↔️ Fahrenheit)