JavaScript is a prototype based language. Another way JavaScript is a functional programming language and function is itself an object. The thing that I am trying to clear is, you can not think almost anything in JavaScript without object. Prototype concept is related to JavaScript Object. After Object , prototype is the most important thing to know in JavaScript if you want to feel love for for it.

Let’s do some programming. We will learn prototype later😁.

const person={
name:"Rayhan",
age:10,
height: 5
}
const student = Object.create(person);
console.log(student) //{}
console.log(student.name) //Rayhan

What have we done ? 😦 Very simple…


  1. Truthy and Falsy Values: I have explained about in about my another article. Please visit Some Basics Of JavaScript .
  2. Null vs Undefined : In JavaScript null means value is nothing , “undefined” is a value that is assigned to a variable when it is declared in the creation or loading phase of the context execution.
  3. Double equal (==) vs triple equal (===), implicit conversion (Very Important): In JavaScript, double equal (==) only compare the values but triple equal (===) compare the values along with type. Triple equal is also called “strict equality”, “identity”. …

  1. Let, const, var

let, const are block (something enclosed by carlibresses) scope but var is function scope. var can be redefined and reassigned in functional scope. On the other hand, ‘let' can’t be redefined but changed in the block scope. ‘const' can’t be redefined and also cann’t be reassigned.

2. Hoisting:

Hoisting is the concept that gives us info about how javascript deals a variable (var) when it is declared. JavaScript does the variable declaration on the top assigning the value of undefined (loading/creation phase of execution phase) and it is called hoisting. …


During the code execution if there is any asynchronous function in the stack, javascript doesn’t execute that function instantly rather it assigns the task to WEB API (In case of Browser), C++ API (Node Js) and do the execution of next task in the call stack. When the WEB API completes the task, it transfers the result to an another data structure called Call Back Queue (follows the First In First Out (FIFO) data structure). If there are many asynchronous functions, they all are transferred to call back queue after the task is completed in the web api. If there…


To answer this question first we need to remember that the way people communicate with each other by some specific language, computer has also its specific way of communication by a language that is called machine language. When we write any code and in the execution time when the browser gets that code browser needs to convert the code into computer language. Now the question is how browser actually converts our code to machine language? Browser converts code to machine language by using JavaScript engine. …


  1. charAt(): This method is used to find out any character of a string at a individual position like if I use ‘rahim’.charAt(1), this will return “r” as value
  2. concat(): This method does nothing but addition of string. Example : ‘rahin’.concat(“,” , ”karim”) and the output will be, “rahim, karim”
  3. endsWith(): This method returns boolean value which that determines whether the string end with given character or not. Example: let str=”my name is rahim”. str.endsWith(“rahim”) will give the output true.
  4. indexof(): This method returns the value of index of a specific character of a string. If it has multiple same character…

1. What is React?

Ans: React is a JavaScript library created by Facebook for building user interfaces to make single page applications. React helps one to create reusable user interface components.

2. How does React Work?

Ans: In memory, React builds a VIRTUAL DOM. Instead of explicitly modifying the browser’s DOM, React builds a simulated DOM in memory and performs all necessary manipulations there before making modifications to the browser DOM.

Virtual DOM:

When we write code in react it creates its own DOM that is called virtual DOM. When we change anything in the component, a new changed DOM is created…

Md Solayman

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