ReactJs-course-meta

1: props

2: state

3 Forms

Course link-->

https://www.youtube.com/watch?v=bMknfKXIFA8&t=1863s

https://www.youtube.com/watch?v=ipOYH_Wi9Xw

https://www.youtube.com/watch?v=4UZrsTqkcW4&t=614s

What is React

ReactJS is an open-source JavaScript library used to create user interfaces in a declarative and efficient way. It is a component-based front-end library responsible only for the view layer of a Model View Controller(MVC) architecture. React is used to create modular user interfaces and promotes the development of reusable UI components that display dynamic data.

React makes it painless to create interactive User interface by using his components.

What is DOM:

A web page is a document that can be either displayed in the browser window or as the HTML source. In both cases, it is the same document but the Document Object Model (DOM) representation allows it to be manipulated

DOM represent the content of a XML or HTML document

DOM allow us to read, access, update the contents of the document

What is JSX (Javascript syntax extension)/ js XML:

--Is a way to structure component rendering using syntax familiar user in React

-- JSX allows us to write HTML in React

-- To use JSX we should apply --> (import React from 'react')

What is the fifference between export and import in ReactJs

Exporting makes the file contents eligible for importing.

The basic idea behind imports and exports is to exchange contents between several JavaScript files.

What does the '.map()' array method do?

Returns a new array. Whatever gets returned from the callback function provided is placed at the same index in the new array. Usually we take the items from the original array and modify them in some way.

What do we usually use '.map()' for in React?

Convert an array of raw data into an array of JSX elements that can be displayed on the page.

Why is using '.map()' better than just creating the components manually by typing them out ?

It makes our code more "self-sustaining " not requiring additional changes whenever the data changes

What is the difference between props and stat

Any time you have changing values that should be saved/displayed, you will likely be using state

What is preventDefault():

The preventDefault() method of the Event interface tells the user agent that if the event does not get explicitly handled, its default action should not be taken as it normally would be.