The Book Of Pure Chaos

L33THaX

// -----------------------------

// 1. Variables and Data Types

// -----------------------------

let name = "Alice"; // string

const age = 30; // number

var isStudent = true; // boolean

let score = null; // null

let grade; // undefined

let person = {

firstName: "John",

lastName: "Doe",

age: 40

};

let colors = ["red", "green", "blue"];

// -----------------------------

// 2. Operators

// -----------------------------

let a = 10, b = 5;

let sum = a + b;

let difference = a - b;

let product = a * b;

let quotient = a / b;

let remainder = a % b;

let isEqual = a === b;

let isNotEqual = a !== b;

let isGreater = a > b;

let isLessOrEqual = a = 18) {

console.log("Adult");

} else {

console.log("Minor");

}

// switch

let gradeLetter = 'B';

switch (gradeLetter) {

case 'A':

console.log("Excellent");

break;

case 'B':

console.log("Good");

break;

default:

console.log("Needs improvement");

}

// -----------------------------

// 4. Loops

// -----------------------------

// for loop

for (let i = 0; i {

console.log("Color:", color);

});

// -----------------------------

// 5. Functions

// -----------------------------

// Regular function

function greet(name) {

return "Hello, " + name;

}

// Arrow function

const greetArrow = (name) => `Hi, ${name}`;

// Function with default parameter

function multiply(x, y = 2) {

return x * y;

}

// -----------------------------

// 6. Objects and Arrays

// -----------------------------

let user = {

name: "Charlie",

age: 35,

greet() {

console.log("Hello!");

}

};

user.greet(); // method call

let fruits = ["apple", "banana", "mango"];

console.log(fruits[1]); // banana

// -----------------------------

// 7. Classes and Inheritance

// -----------------------------

class Animal {

constructor(name) {

this.name = name;

}

speak() {

console.log(`${this.name} makes a noise.`);

}

}

class Dog extends Animal {

speak() {

console.log(`${this.name} barks.`);

}

}

const dog = new Dog("Buddy");

dog.speak(); // Buddy barks.

// -----------------------------

// 8. Error Handling

// -----------------------------

try {

throw new Error("Something went wrong!");

} catch (err) {

console.error("Caught error:", err.message);

} finally {

console.log("Always runs.");

}

// -----------------------------

// 9. Asynchronous JavaScript

// -----------------------------

// Promise

const fetchData = () => {

return new Promise((resolve, reject) => {

setTimeout(() => resolve("Data received"), 1000);

});

};

fetchData().then(data => console.log(data));

// async/await

async function getData() {

const result = await fetchData();

console.log("Async result:", result);

}

getData();

// -----------------------------

// 10. DOM Manipulation (Browser)

// -----------------------------

// Assume there is a Click me in HTML

document.getElementById("myBtn").addEventListener("click", () => {

alert("Button was clicked!");

});

// -----------------------------

// 1. Variables and Data Types

// -----------------------------

let name = "Alice"; // string

const age = 30; // number

var isStudent = true; // boolean

let score = null; // null

let grade; // undefined

let person = {

firstName: "John",

lastName: "Doe",

age: 40

};

let colors = ["red", "green", "blue"];

// -----------------------------

// 2. Operators

// -----------------------------

let a = 10, b = 5;

let sum = a + b;

let difference = a - b;

let product = a * b;

let quotient = a / b;

let remainder = a % b;

let isEqual = a === b;

let isNotEqual = a !== b;

let isGreater = a > b;

let isLessOrEqual = a = 18) {

console.log("Adult");

} else {

console.log("Minor");

}

// switch

let gradeLetter = 'B';

switch (gradeLetter) {

case 'A':

console.log("Excellent");

break;

case 'B':

console.log("Good");

break;

default:

console.log("Needs improvement");

}

// -----------------------------

// 4. Loops

// -----------------------------

// for loop

for (let i = 0; i {

console.log("Color:", color);

});

// -----------------------------

// 5. Functions

// -----------------------------

// Regular function

function greet(name) {

return "Hello, " + name;

}

// Arrow function

const greetArrow = (name) => `Hi, ${name}`;

// Function with default parameter

function multiply(x, y = 2) {

return x * y;

}

// -----------------------------

// 6. Objects and Arrays

// -----------------------------

let user = {

name: "Charlie",

age: 35,

greet() {

console.log("Hello!");

}

};

user.greet(); // method call

let fruits = ["apple", "banana", "mango"];

console.log(fruits[1]); // banana

// -----------------------------

// 7. Classes and Inheritance

// -----------------------------

class Animal {

constructor(name) {

this.name = name;

}

speak() {

console.log(`${this.name} makes a noise.`);

}

}

class Dog extends Animal {

speak() {

console.log(`${this.name} barks.`);

}

}

const dog = new Dog("Buddy");

dog.speak(); // Buddy barks.

// -----------------------------

// 8. Error Handling

// -----------------------------

try {

throw new Error("Something went wrong!");

} catch (err) {

console.error("Caught error:", err.message);

} finally {

console.log("Always runs.");

}

// -----------------------------

// 9. Asynchronous JavaScript

// -----------------------------

// Promise

const fetchData = () => {

return new Promise((resolve, reject) => {

setTimeout(() => resolve("Data received"), 1000);

});

};

fetchData().then(data => console.log(data));

// async/await

async function getData() {

const result = await fetchData();

console.log("Async result:", result);

}

getData();

// -----------------------------

// 10. DOM Manipulation (Browser)

// -----------------------------

// Assume there is a Click me in HTML

document.getElementById("myBtn").addEventListener("click", () => {

alert("Button was clicked!");

});