JavaScript Loops

// for (initialization; condition; update)
for (let i = 0; i < 5; i++) {
  console.log(i);  // 0 1 2 3 4
}

// Loop through an array by index
const fruits = ["apple", "banana", "mango"];
for (let i = 0; i < fruits.length; i++) {
  console.log(fruits[i]);
}

// Count down
for (let i = 10; i >= 0; i--) {
  console.log(i);
}

const courses = ["HTML", "CSS", "JavaScript"];

for (const course of courses) {
  console.log(course);
}
// HTML, CSS, JavaScript

// With index using entries()
for (const [index, course] of courses.entries()) {
  console.log(`${index + 1}. ${course}`);
}
// 1. HTML, 2. CSS, 3. JavaScript

const prices = [100, 250, 75];

prices.forEach((price, index) => {
  console.log(`Item ${index + 1}: ₹${price}`);
});
// Item 1: ₹100, Item 2: ₹250, Item 3: ₹75

// Note: forEach cannot be stopped with break — use for...of instead

let count = 0;
while (count < 3) {
  console.log(count);
  count++;
}
// 0 1 2

// Use while when you don't know iterations in advance
let input = "";
while (!input) {
  input = prompt("Enter your name:");
}

const student = { name: "Priya", age: 22, grade: "A" };

for (const key in student) {
  console.log(`${key}: ${student[key]}`);
}
// name: Priya, age: 22, grade: A

// Prefer Object.keys() / Object.entries() for cleaner code
Object.entries(student).forEach(([key, val]) => console.log(key, val));

// break — exit the loop entirely
for (let i = 0; i < 10; i++) {
  if (i === 5) break;
  console.log(i);  // 0 1 2 3 4
}

// continue — skip this iteration
for (let i = 0; i < 6; i++) {
  if (i % 2 === 0) continue;
  console.log(i);  // 1 3 5 (skips even numbers)
}