🎯 Learning Objectives

By the end of this lecture, students will be able to:

• Use modern array looping methods (forEach, map, filter, find)
• Understand which methods return a new array and which change the original
• Detect arrays using Array.isArray()
• Combine and copy arrays using the spread operator (...)
• Destructure arrays
• Understand how sorting works in JavaScript
• Deal with custom/non-sequential array indexes (sparse arrays)
• Write more readable and modern JavaScript code

🟨 1. forEach() — Loop Over an Array

✔ What it does

Executes a function for each item in the array.

✔ Does it return a new array?

❌ No, it always returns undefined.

✔ Does it change the original array?

❌ No, unless you manually modify items.

Example:

let fruits = ["Apple", "Mango", "Banana"];

fruits.forEach((fruit, index) => {
  console.log(index, fruit);
});