React Redux: As the name suggests it’s a javascript library created by Facebook and it is the most popular javascript library and used for building User Interfaces(UI) specifically for single-page applications. React js enables the developer to break down complicated UI into a simpler one. We can make particular changes in data of web applications without refreshing the page. React allows creating reusable components.

Advantages of React js

Easy to learn and Easy to use:

 React is easy to learn and simple to use and comes with lots of good paperwork, tutorials, and training resources. You can use plain JavaScript to create a web application and then handle it using this. It is also known as the V in the MVC (Model View Controller) pattern.

Virtual DOM:

Virtual DOM is a memory-representation of Real DOM(Document Object Model). A virtual DOM is a lightweight JavaScript object that is originally just a copy of Real DOM.

 It helps to improve performance and thus the rendering of the app is fast.

CodeReability increases with JSX:

JSX stands  for javascript XML.This is a sort of file used by React which utilizes javascript expressiveness along with HTML like template syntax.JSX makes your code simple and better.

Reusable Components:

Each component has its logic and controls its own rendering and can be reused wherever you need it. Component reusability helps to create your application simpler and increases performance.

Need for React Redux:

1) The core problem with React js is state Management.

2) There may be the same data to display in multiple places. Redux has a different approach, redux offers a solution storing all your application state in one place called store. The component then dispatch state changes to the store not directly to the component.

What is Redux??

Redux is a predictable state container for javascript applications. It helps you write applications that behave consistently and run in different environments and are easy to test. Redux mostly used for state Management.

Advantages of Using Redux

Redux makes state Predictable:

In redux the state is Predictable when same state and action passed to a reducer. Its always produce same the same result. since reducers are pure functions. The state is also unchangeable and never changed. This allow us for arduous task such as infinite redo and undo.

Maintainability:

Redux is strict about how code should be organized, which makes understanding the structure of any redux application easier for someone with redux knowledge. This generally makes the maintenance easier.

Ease of testing:

Redux apps can be easily tested since functions are used to change the state of pure functions.

Redux-data flow (diagram)

Redux is composed of the following components:

• Action
• Reducer
• Store 
• View

Action: Actions are the payload of information that sends data from your application to your store. Actions describe the fact that something happens but do not specify how the application state changes in the response.

Action must have a type property that indicates types of action being performed

they must be defined as a string constant.

Action-type:

export const ADD_ITEM=’ADD_ITEM,

Action-creator:

import * as actionType from ‘./action-types’

function addItem(item) {

   return {

       type: actionType.ADD_ITEM,

       payload:item

   }

}

Reducer: Reducer is a pure function which specifies how application state change in response to an action. Reducer handle action dispatch by the component. Reducer takes a previous state and action and returns a new state. Reducer does not manipulate the original state passed to them but make their own copies and update them.

function reducer(state = initialState, action) {

   switch (action.type) {

       case ‘ADD_ITEM’:

           return Object.assign({}, state,

               { items: [ …state.items,

                   {

                       item: action.payload

                   }

                   ]

               })

           default:

           return state

   }

}

Things you should never do inside a reducer

Mutate its arguments

Perform side effects like API calls

Calling non-pure functions Like Math.random()

Store

A store is an object that brings all components to work together. It calculates state changes and then notifies the root reducer about it. Store keeps the state of your whole application. It makes the development of large applications easier and faster. Store is accessible to each component

import { createStore } from ‘redux’

import todoApp from ‘./reducers’

let store = createStore(reducer);

View:

The only purpose of the view is to display the data passed by the store.

Conclusion:-

So coming to the conclusion why we should use React with Redux is because redux solves the state management problem. Redux offers solutions storing your whole application state in a single place that you can say it central store which is accessible to each component.