Web Development - HTML, CSS & JavaScript
Learn to code and become a Web Developer with HTML, CSS, JavaScript , Reactjs, Wordpress, PHP, Mern & Nodejs knowledge Managed by: @love_data
Mostrar más📈 Análisis del canal de Telegram Web Development - HTML, CSS & JavaScript
El canal Web Development - HTML, CSS & JavaScript (@javascript_courses) en el segmento lingüístico de Inglés es un actor destacado. Actualmente la comunidad reúne a 55 666 suscriptores, ocupando la posición 2 378 en la categoría Tecnologías y Aplicaciones y el puesto 6 196 en la región India.
📊 Métricas de audiencia y dinámica
Desde su creación el невідомо, el proyecto ha mostrado un crecimiento acelerado, reuniendo a 55 666 suscriptores.
Según los últimos datos del 26 octubre, 2026, el canal mantiene una actividad estable. En los últimos 30 días la variación de miembros fue de -4, y en las últimas 24 horas de -3, conservando un alto alcance.
- Estado de verificación: No verificado
- Tasa de interacción (ER): El promedio de interacción de la audiencia es 3.66%. Durante las primeras 24 horas tras publicar, el contenido suele obtener 1.17% de reacciones respecto al total de suscriptores.
- Alcance de las publicaciones: Cada publicación recibe en promedio 2 037 visualizaciones. En el primer día suele acumular 652 visualizaciones.
- Reacciones e interacción: La audiencia responde de forma activa: el promedio de reacciones por publicación es 3.
- Intereses temáticos: El contenido se centra en temas clave como javascript, css, object, html, array.
📝 Descripción y política de contenido
El autor describe el recurso como un espacio para expresar opiniones subjetivas:
“Learn to code and become a Web Developer with HTML, CSS, JavaScript , Reactjs, Wordpress, PHP, Mern & Nodejs knowledge
Managed by: @love_data”
Gracias a la alta frecuencia de actualizaciones (últimos datos recibidos el 27 octubre, 2026), el canal mantiene la vigencia y un amplio alcance. La analítica demuestra que la audiencia interactúa activamente con el contenido, lo que lo convierte en un punto de referencia dentro de la categoría Tecnologías y Aplicaciones.
console.log(Object.keys(person));
Output: ["name","age"]
🚀 17. Object.values()
Returns all values.
console.log(Object.values(person));
Output: ["Deepak",25]
🔥 18. Object.entries()
Returns key-value pairs. console.log(Object.entries(person));
Output: [["name","Deepak"], ["age",25]]
📦 19. Destructuring Objects
Extract values easily.
const person = { name:"Deepak", age:25 };
const { name, age } = person;
⚡ 20. Spread Operator
Copy objects.
const person = { name:"Deepak" };
const updated = {...person, city:"Pune" };
🎯 Real Interview Example
Array of Objects
const employees = [
{ id:1, name:"John" },
{ id:2, name:"Mike" }
];
console.log(employees[0].name);
Output: John
⭐ Most Important Topics For Interviews
🔥 Arrays
🔥 Objects
🔥 map()
🔥 filter()
🔥 reduce()
🔥 Destructuring
🔥 Spread Operator
🔥 Object.keys()
🔥 Object.values()
🔥 Array of Objects
📝 Mini Practice Questions
Easy:
✅ Find largest number in array,
✅ Sum all array elements,
✅ Count array length
Medium:
✅ Remove duplicates,
✅ Find second largest number,
✅ Reverse array
Advanced:
✅ Group objects by property,
✅ Custom map() method,
✅ Flatten nested arrays
Double Tap ❤️ For More
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1.59 ₽ · /balance_helpconst fruits = ["Apple", "Mango", "Banana"];
Access Elements:
console.log(fruits[0]);
Output: Apple
Important: Array indexing starts from 0.
⚡ 2. Creating Arrays
Method 1: const numbers = [10, 20, 30];
Method 2: const numbers = new Array(10, 20, 30);
🔥 3. Array Methods
push() Adds element at the end.
const arr = [1, 2];
arr.push(3);
console.log(arr);
Output: [1, 2, 3]
pop() Removes last element. arr.pop();
unshift() Adds element at beginning. arr.unshift(0);
shift() Removes first element. arr.shift();
🔄 4. Loop Through Arrays
for Loop
const nums = [1,2,3];
for(let i=0; i<nums.length; i++){
console.log(nums[i]);
}
for...of
for(let num of nums){
console.log(num);
}
🎯 5. map()
Creates a new array by transforming elements.
Example:
const nums = [1,2,3];
const doubled = nums.map(num => num * 2);
console.log(doubled);
Output: [2, 4, 6]
🔥 6. filter()
Returns elements matching condition.
Example:
const nums = [1,2,3,4,5];
const even = nums.filter(num => num % 2 === 0);
console.log(even);
Output: [2, 4]
🚀 7. reduce()
Reduces array to single value.
Example:
const nums = [1,2,3,4];
const sum = nums.reduce((total,num) => total + num, 0);
console.log(sum);
Output: 10
🧩 8. find()
Returns first matching element.
const users = [10,20,30,40];
const result = users.find(num => num > 20);
console.log(result);
Output: 30
📋 9. includes()
Checks if value exists.
const fruits = ["Apple","Mango"];
console.log(fruits.includes("Apple"));
Output: true
🔥 10. Remove Duplicates
const nums = [1,2,2,3,3];
const unique = [...new Set(nums)];
console.log(unique);
Output: [1, 2, 3]
📦 PART 2: JavaScript Objects
🧠 11. What is an Object?
An object stores data in key-value pairs.
Example:
const person = {
name: "Deepak",
age: 25,
city: "Bengalore"
};
⚡ 12. Access Object Properties
Dot Notation: console.log(person.name);
Bracket Notation: console.log(person["name"]);
🔥 13. Add New Property
person.country = "India";
console.log(person);
❌ 14. Delete Property
delete person.city;
🔄 15. Loop Through Objects
for...in
for(let key in person){
console.log(key, person[key]);
}function reverseString(str) {
return str.split('').reverse().join('');
}
4️⃣ Find the max number in an array
const max = Math.max(...arr);
5️⃣ Write a function to check if a number is prime
function isPrime(n) {
if (n < 2) return false;
for (let i = 2; i <= Math.sqrt(n); i++) {
if (n % i === 0) return false;
}
return true;
}
6️⃣ What is closure in JavaScript?
Answer:
A function that remembers variables from its outer scope even after the outer function has returned.
7️⃣ What is event delegation?
Answer:
Attaching a single event listener to a parent element to manage events on its children using event.target.
8️⃣ Difference between == and ===
Answer:
- == checks value (with type coercion)
- === checks value + type (strict comparison)
9️⃣ What is the Virtual DOM?
Answer:
A lightweight copy of the real DOM used in React. React updates the virtual DOM first and then applies only the changes to the real DOM for efficiency.
🔟 Write code to remove duplicates from an array
const uniqueArr = [...new Set(arr)];
React ❤️ for morefunction greet(name, callback) {
console.log("Hello " + name);
callback();
}
function done() {
console.log("Completed");
}
• greet("Deepak", done);
Output:
• Hello Deepak
• Completed
🚀 14. Higher Order Functions
Higher Order Functions -> functions that:
• Accept functions as arguments
• Return functions
Example:
function operation(callback) {
callback();
}
• operation(() => {
console.log("Executed");
});
⚡ 15. Closures
Closures -> one of the most important interview topics.
A closure -> allows a function to remember variables from its outer scope.
Example:
function counter() {
let count = 0;
return function() {
count++;
console.log(count);
};
}
const increment = counter();
• increment();
• increment();
Output:
• 1
• 2
🎯 16. Recursive Functions
Recursive -> a function calling itself.
Example:
function countdown(n) {
if(n === 0) {
return;
}
console.log(n);
countdown(n - 1);
}
• countdown(5);
Output:
• 5
• 4
• 3
• 2
• 1
🧮 17. Practical Example — Sum of Array
function sumArray(arr) {
return arr.reduce((sum, num) => sum + num, 0);
}
console.log(sumArray([1, 2, 3]));
Output:
• 6
⭐ Important Interview Topics
Focus heavily on:
• 🔥 Function Declaration
• 🔥 Function Expression
• 🔥 Arrow Functions
• 🔥 Scope
• 🔥 Closures
• 🔥 Callback Functions
• 🔥 Higher Order Functions
• 🔥 Recursion
• 🔥 Hoisting
📝 Mini Practice Questions
Easy
• ✅ Create calculator function
• ✅ Find maximum of two numbers
• ✅ Check even or odd
Medium
• ✅ Reverse string
• ✅ Find factorial
• ✅ Check palindrome
Advanced
• ✅ Implement debounce
• ✅ Implement throttle
• ✅ Create custom map() function
Double Tap ❤️ For More
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1.39 ₽ · /balance_helpfunction greet() {
console.log("Hello World");
}
Calling the Function:
• greet();
Output:
• Hello World
⚡ 2. Function Declaration
The most common way -> create a function.
Syntax:
function functionName() {
}
Example:
function welcome() {
console.log("Welcome to JavaScript");
}
• welcome();
🔥 3. Function Parameters
Parameters -> variables that receive values.
Example:
function greet(name) {
console.log("Hello " + name);
}
• greet("Deepak");
Output:
• Hello Deepak
🎯 4. Multiple Parameters
function add(a, b) {
console.log(a + b);
}
• add(10, 20);
Output:
• 30
🔄 5. Return Statement
return -> sends a value back from a function.
Example:
function add(a, b) {
return a + b;
}
let result = add(10, 20);
console.log(result);
Output:
• 30
🧩 6. Function Expression
A function -> stored inside a variable.
Example:
const greet = function() {
console.log("Hello");
};
• greet();
Difference:
Concept -> Function Declaration vs Function Expression
• Hoisted -> Yes vs Not Hoisted
• Defined -> separately vs Stored in variable
⚡ 7. Arrow Functions (ES6)
Modern way -> write functions.
Traditional Function:
function add(a, b) {
return a + b;
}
Arrow Function:
const add = (a, b) => {
return a + b;
};
Short Form:
const add = (a, b) => a + b;
📦 8. Default Parameters
Default values -> used when arguments are not passed.
Example:
function greet(name = "Guest") {
console.log(name);
}
• greet();
Output:
• Guest
🧠 9. Rest Parameters
Rest parameters -> collect multiple arguments into an array.
Example:
function sum(...numbers) {
console.log(numbers);
}
• sum(1, 2, 3, 4);
Output:
• [1, 2, 3, 4]
🚀 10. Scope in JavaScript
Scope -> determines where variables can be accessed.
Global Scope
let name = "Deepak";
function show() {
console.log(name);
}
• Accessible -> everywhere
Local Scope
function show() {
let age = 25;
console.log(age);
}
• Accessible -> only inside function
🔒 11. Block Scope
Variables -> declared using let and const.
if(true) {
let age = 25;
console.log(age);
}
Outside block:
console.log(age);
❌ Error
🧠 12. What is Hoisting?
Hoisting -> JavaScript moves declarations to the top before execution.
Example:
sayHello();
function sayHello() {
console.log("Hello");
}
• Works -> because function declarations are hoisted
🔥 13. Callback Functions
Callback -> function passed as an argument to another function.
Example: