What is JavaScript?

Md Nayem Hossain — Thu, 17 Nov 2022 17:55:32 +0000

JavaScript is a high-level, often just-in-time compiled programing or scripting language. It has dynamic typing, prototype-based object-orientation, and first-class functions. It is multi-paradigm, supporting event-driven, functional, and imperative programming styles.

Note:

High-Level → Human Understandable.

Just-in-time Compilation → Dynamic Compilation OR Runtime Compilation. Means, a way of executing computer code that performs compilation during the execution of a program (at run time) rather than before execution.

Dynamic Type → Where the interpreter assigns variables a type at runtime based on the variable's value at the time. It means that JS does not require the explicit declaration of the variables before they're used.

Prototype-based object-orientation → Prototype-based object-orientation is a style of object-oriented programming in which classes are not explicitly defined, but rather derived by adding properties and methods to an instance of another class.

First-class Functions → When functions are treated like any other variables.

Multi-paradigm → Multi paradigm means the language is general-purpose or flexible. JavaScript can be used for declarative (functional) or imperative (object-oriented) programming styles.

Event-Driven → Event-driven programming is a programming paradigm in which the flow of the program is determined by events such as user actions (mouse clicks, key presses), sensor outputs, or message passing from other programs or threads.

What is Virtual DOM? What are the differences between virtual and real DOM?

Md Nayem Hossain — Fri, 11 Nov 2022 19:05:19 +0000

Virtual DOM is a virtual representation of the real DOM. Basically, it’s just a copy of the real DOM.
The main difference between them is- a virtual DOM object has all the same properties as a real DOM, but it can't display a page into the browser directly, just like the real DOM.

In summary, here’s basically what happens when we try to update the DOM in React:

i. The entire virtual DOM gets updated.
ii. The virtual DOM gets compared to what it looked like before we updated it. React figures out which objects have changed.
iii. The changed objects only get updated on the real DOM.
iv. Changes in the real DOM cause the screen to change.

DEV Community: Md Nayem Hossain

What is JavaScript?

What is Virtual DOM? What are the differences between virtual and real DOM?