javascript advanced concepts

Javascript Advanced Concepts

Javascript is a powerful language that is used to build interactive web applications. However, to become a proficient Javascript developer, one must have a good understanding of advanced concepts. In this post, I will discuss some of the most important Javascript advanced concepts.


A closure is an inner function that has access to the outer function's variables and parameters. It allows you to create private variables and methods in Javascript. Here is an example:

function outerFunction() {
  const outerVariable = 'I am an outer variable';
  function innerFunction() {
  return innerFunction;

const innerFunction = outerFunction();
innerFunction(); // logs 'I am an outer variable'

Prototypal Inheritance

Prototypal inheritance is a way to share methods and properties between objects. In Javascript, each object has a prototype object, which it inherits methods and properties from. Here is an example:

function Person(name) { = name;

Person.prototype.sayHello = function() {
  console.log(`Hello, my name is ${}`);

const person = new Person('Raju');
person.sayHello(); // logs 'Hello, my name is Raju'

Asynchronous Programming

Asynchronous programming in Javascript allows you to execute code without blocking the main thread. This is essential for building responsive web applications. Here is an example using promises:

function fetchData() {
  return new Promise((resolve, reject) => {
    setTimeout(() => {
      resolve('Data fetched successfully');
    }, 1000);

fetchData().then((data) => {
}); // logs 'Data fetched successfully' after 1 second


Generators are functions that can be paused and resumed. They allow you to write asynchronous code in a synchronous style. Here is an example:

function* generator() {
  yield 1;
  yield 2;
  yield 3;

const iterator = generator();

console.log(; // logs { value: 1, done: false }
console.log(; // logs { value: 2, done: false }
console.log(; // logs { value: 3, done: false }
console.log(; // logs { value: undefined, done: true }

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