📌 What Are Arrow Functions?

Arrow functions are a shorter way to write functions in JavaScript.

They reduce extra code (boilerplate) and look cleaner.

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📌 1️⃣ Normal Function vs Arrow Function

✅ Normal Function

function greet(name) {
  return "Hello " + name;
}

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✅ Arrow Function

const greet = (name) => {
  return "Hello " + name;
};

See how it removes function keyword?

That’s the main idea.

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📌 Basic Arrow Function Syntax

const functionName = (parameters) => {
  // code
};

Breakdown:

(parameters) => { }
      ↑          ↑
   inputs      function body

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📌 Arrow Function with One Parameter

If there is only one parameter, brackets are optional.

const greet = name => {
  return "Hello " + name;
};

Both are correct:

(name) => {}
name => {}

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📌 Arrow Function with Multiple Parameters

If there are multiple parameters, use brackets.

const add = (a, b) => {
  return a + b;
};

console.log(add(5, 3));  // 8

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📌 Implicit Return vs Explicit Return

This is very important 🔥

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🔹 Explicit Return (with return keyword)

const square = (num) => {
  return num * num;
};

We used { } and return.

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🔹 Implicit Return (No return keyword)

If function has only one line, we can remove {} and return.

const square = num => num * num;

console.log(square(4));  // 16

👉 This automatically returns the value.

That is called implicit return.

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📌 Another Example

Normal function:

function multiply(a, b) {
  return a * b;
}

Arrow version:

const multiply = (a, b) => a * b;

Cleaner and modern ✅

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📌 Basic Difference: Normal vs Arrow Function

Normal Function	Arrow Function
Uses function keyword	Uses =>
More code	Shorter
Has its own this	Does not have its own this
Traditional style	Modern style

⚠ For now, just remember:

Arrow functions are mostly used for short and simple tasks.

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📊 Diagram Idea – Transformation

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

          ↓

Arrow Function
const add = (a, b) => a + b;

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📊 Syntax Breakdown

const add = (a, b) => a + b;
      ↑       ↑         ↑
   variable  inputs    return value

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🎓 Assignment Practice

1️⃣ Write Normal Function to Calculate Square

function square(num) {
  return num * num;
}

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2️⃣ Rewrite Using Arrow Function

const square = num => num * num;

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3️⃣ Even or Odd Using Arrow Function

const checkEvenOdd = num =>
  num % 2 === 0 ? "Even" : "Odd";

console.log(checkEvenOdd(4)); // Even

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4️⃣ Use Arrow Function Inside map()

let numbers = [1, 2, 3, 4];

let doubled = numbers.map(num => num * 2);

console.log(doubled);

Output:

[2, 4, 6, 8]

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🌟 Final Understanding

Arrow functions:

• Are shorter

• Improve readability

• Are widely used in modern JavaScript

• Work great with map(), filter(), etc.