React redux hooks example

React redux hooks example DEFAULT

How to Hook Redux in a React App

You’ll notice that the actual data about each food item is stored by its id in the menuById key of the store. The menuIdList array only contains a list of ids per diet. There are three main benefits of storing data this way-

  1. Reduce duplicate copies — If we had stored data directly in arrays then some food items would be duplicated in both all type and veg type.
  2. Faster item access — Since we’re storing stuff by id, if we know the id accessing it will happen in O(1) instead of digging through an array which in best case scenario is O(log n).
  3. Filter results get cached — Suppose we get the items for a diet via an API call. We can cache the food item ids per diet so that when user selects a diet again we can pick the ids from cache instead of making an API call.

This technique is called normalization.

Similar to this cartByIds only store a mapping of item id and its quantity. The only downside is that we can’t just directly show data of store to user we’ll need to do some pre-processing to mold the data into the shape the various views requires. We’ll cover this when we talk about selectors.

Now let’s write the logic for CHANGE_DIET action in the reducer.

Here we get the current value of diet from the store and then return a new state which has only two differences- The diet value is opposite of the previous one and the cartByIds is empty.

Notice that our reducer contains the actual toggling logic and is not treated as a dumb layer just to store whatever data comes in action payload.

Next, we have to deal with LOAD_MENU action.

When LOAD_MENU is dispatched, it’ll send an array of food items in the menu key of payload. We put this array into our store like this-

  1. Traverse the menu array and store each item by id in menuById object.
  2. Make an array of ids for all items.
  3. Make an array of ids for only veg items.
  4. Return the new state with changes in menuById and menuIdList.

Similarly, we have implemented ADD_TO_CART and REMOVE_FROM_CART. We store data (quantity etc.) for each item by its id inside cartByIds. When user adds an item to cart, the dispatched action gets that item’s id in payload. Then we find the item’s quantity in cartByIds, change it by 1 and again store it.

Redux Store

We make a function in which we create a Redux store, pass the foodReducer to it. We also enable the Redux DevTools extension for better debugging and then export this function.

Then in index.js, we create a store, wrap the App component inside Provider component from react-redux package and pass the store as a prop to the Provider.

The App.js file is our top most parent component React renders. The whole file is doing the following stuff —

  1. Read the diet from store and update it when user toggles the Veg Only checkbox.
  2. Triggers an API call to load the menu.
  3. Pass the API status to Message component so user is notified when API is done loading.
  4. Get the loaded menu from Redux store and pass it to MenuList component.
  5. Render PaymentFooter component.

Let’s look at how some of these things are done —

Diet Toggler

If user clicks on the Veg Only checkbox then we need to only show the vegetarian items. So we need a way to get the diet value from the store and also update it.

To get data from Redux store, we use the useSelector hook from the react-redux package. The useSelector hook takes a function (selector). This function gets the entire Redux store state as a parameter and its job is to return only the state needed. For this case we only need the diet state.

We get the dispatch function from useDispatch hook and we dispatch an action of type CHANGE_DIET from the handleVegToggle event handler. At last we plug the diet value and the handleVegToggle event handler into the checkbox.

API Loader

All of the API loading logic is abstracted away into the useLoadFoodData hook. It does two things-

  1. Track the API loading status in a React state named stateAPIStatus and return it so App component knows about it.
  2. When API call finishes, dispatch the LOAD_MENU action to store the API data in Redux store.

The code is pretty self-explanatory.

The App component uses the hook like so

const stateAPIStatus = useLoadFoodData();

We pass stateAPIStatus to Message component which will render an aria live region to notify user when API data is being fetched or if it errors.

Display Menu

As we previously saw, useLoadFoodData hook takes care of updating the store with the menu data from API. So now App component can get the menu from store using a selector and pass the data to the MenuList component as a prop.

But you’ll notice that to get diet and menuList we’re using two useSelector and both usage are slightly different. This raises three questions.

  1. Why are we using a separate selectorMenu instead of inline function?
  2. Why are we passing shallowEqual function as a second argument to useSelector.
  3. Why do we need two separate useSelectors in the first place?

The first question has a simple answer, since we stored data in Redux store by id we need to do some simple pre-processing in the selector to return the array of food items with complete details. It is more readable if we keep it in a function outside the component and this way we can also re-use the selector in other components.

We would also need to do this if we were using memoized selectors with something like reselect. More details in the docs.

To answer the next two questions we’ll need to understand selectors in-depth.

The function that we pass to useSelector hook as first argument is called a selector. The selectors are run whenever any value in the Redux store changes. But to improve performance Redux does one optimization. It does a referential equality check between the old and new value returned by the selector.

In our diet selector, it was just returning a string. When the store updates, the diet selector runs and then useSelector does this comparison

const oldDietVal = getOldVal();
const newDietVal = selectorMenu(storeState);newDietVal === oldDietVal

If by referential equality, both values are same then useSelector just returns the old value.

Now let’s look at our selectorMenu selector function.

First we create a fresh new menuList array. Then we find all the ids for the user’s currently selected diet and then populate menuListwith the data of each id. At last we return the menuList array.

But here’s the thing, as we saw Redux only does a referential equality check between the old and new value and in JavaScript.

[] === [] // is always false

That means useSelector will always return the new array. It’s a problem because when we use the returned menuList array in a useEffect or pass it to MenuList child component, React will notice that the array is different from last time and will always update.

Above you’ll notice that when user toggles the Veg Only checkbox then the menuList changes so effect runs like expected but when user adds an item to the cart then there is no perceived change in menuList but still the effect runs and we want to avoid this.

To avoid this performance penalty we can pass a custom comparison function as the second argument to useSelector. In our case we provide the shallowEqual function (from react-redux package). Now useSelector will do a shallow comparison instead of referential equality between the new and old value.

Notice that in the above example, React only triggers updates when user clicks on Veg Only but doesn’t do anything when user adds an item to the cart.

If you understood this then you’d also figure out why we used two useSelector and not return a big object through one useSelector. This kind of selector would have to return an object like this

{
diet: 'veg',
menuList: [],
}

Since it always returns a new object which also has a newly created menuList array the shallow comparison check will start failing again. To solve this we might provide a deep comparison as the second argument to useSelector but that can be an expensive operation. So its a good idea to just stick with separate selectors for individual states.

Just like we moved away from one componentDidMount to independent useEffects, we need to move away from one mapStateToProps to multiple useSelectors.

In the reducer we went through two actions CHANGE_DIET, LOAD_MENU. We dispatched them from components, custom hooks and at last learned how to get data from store using selectors.

The code for integrating UI components with Redux can be found in this Comps.js file on GitHub. In the same file you’ll see how we display the total price in PaymentFooter component.

Sours: https://blog.bitsrc.io/how-to-hook-redux-in-a-react-app-e1de2f6fa094

Introduction React-Redux using Hooks (useSelector && useDispatch)

Introduction:

Before reading this article you should know about React & Redux, its working.

This article is about React-Redux Hooks. We will go through below main points in this article:

* Hooks for Redux.

* How to use Hook.

* How to use Hook.

1. Hooks for Redux

Before Hooks, we always used a which is a higher-order component and wrapper to our component, read values from the Redux store.

takes two arguments, both optional:

    called every time the store state changes. It receives the entire store state and should return an object of data this component needs.

    This parameter can either be a function, or an object. If it’s a function, it will be called once on component creation. It will receive dispatch as an argument and should return an object full of functions that use dispatch to dispatch actions.

    more about connect()

    Let's move towards react-redux hooks. React-Redux now offers a set of hook APIs as an alternative to existing Higher-Order Component. These APIs allow you to subscribe to the Redux store and dispatch actions, without having to wrap your components in . By using the Hook API with Function components, components are kept small and the code remains clean.

    Hooks:

    2. useDispatch():

    hook is equivalent of .

    We will invoke and store it to a variable, . This hook returns a to the from the Redux store. You may use it to dispatch actions as needed.
    And we dispatch it by calling dispatch passing in the return value from the action creator.

    How to use

    Below is the small component where using and

    complete code in GITHUB redux-hooks

    3.useSelector():

    hook is equivalent of

    is a function that takes the current state as an argument and returns whatever data you want from it and it allows you to store the return values inside a variable within the scope of you functional components instead of passing down as props

    complete code in GITHUB redux-hooks

    useStore():

    hook returns a reference to the same Redux store that was passed into component.

    This hook should probably not be used frequently. Prefer useSelector() as your primary choice. However, this may be useful for less common scenarios that do require access to the store, such as replacing reducers.

    complete code in GITHUB redux-hooks

    If you wanna learn more about and here it's official link React Redux Hooks

    Further improvement, suggestion or help. Welcome :)

    Sours: https://dev.to/bangash1996/introduction-react-redux-using-hooks-useselector-usedispatch-26ch
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    React Hooks + Redux: CRUD example with Axios and Rest API

    In this tutorial, I will show you how to build a React Redux Hooks + Axios example by a CRUD Application to consume Rest API.

    Full Article: https://bezkoder.com/react-hooks-redux-crud/

    Overview of React Hooks Redux CRUD example

    We will build a React Redux Tutorial Application with Rest API calls in that:

    • Each Tutorial has id, title, description, published status.
    • We can create, retrieve, update, delete Tutorials.
    • There is a Search bar for finding Tutorials by title.

    Here are screenshots of our React Redux CRUD Application.

    react-hooks-redux-crud-example-create-tutorial

    react-hooks-redux-crud-example-retrieve-tutorial

    • Click on Edit button to update a Tutorial:

    react-hooks-redux-crud-example-retrieve-one-tutorial

    On this Page, you can:

    • change status to Published using Publish button
    • delete the item using Delete button
    • update the item details with Update button

    react-hooks-redux-crud-example-update-tutorial

    • Search Tutorials by title:

    react-hooks-redux-crud-example-search-tutorial

    • Check Redux State with Dev-tool:

    react-hooks-redux-crud-example-check-redux-state

    This React Client consumes the following Web API:

    MethodsUrlsActions
    POST/api/tutorialscreate new Tutorial
    GET/api/tutorialsretrieve all Tutorials
    GET/api/tutorials/:idretrieve a Tutorial by
    PUT/api/tutorials/:idupdate a Tutorial by
    DELETE/api/tutorials/:iddelete a Tutorial by
    DELETE/api/tutorialsdelete all Tutorials
    GET/api/tutorials?title=[keyword]find all Tutorials which title contains

    You can find step by step to build a Server like this in one of these posts:

    React Hooks Redux CRUD Component Diagram with Router & Axios

    Now look at the React components that we're gonna implement:

    react-hooks-redux-crud-example-components

    – The component is a container with React . It has that links to routes paths.

    – Three pages that dispatch actions to which uses to call Rest API:

    • gets and displays Tutorials.
    • has form for editing Tutorial's details based on .
    • has form for submission new Tutorial.

    – uses to make HTTP requests and receive responses.

    React Hooks + Redux with API example

    This diagram shows how Redux elements work in our React Hooks Application:

    react-hooks-redux-crud-example-redux-store

    We're gonna create Redux for storing data. Other React Components will work with the Store via dispatching an or getting value using React-Redux Hooks API.

    The will take the action and return new .

    Technology

    • React 17/16
    • react-redux 7.2.3
    • redux 4.0.5
    • redux-thunk 2.3.0
    • react-router-dom 5.2.0
    • axios 0.21.1
    • bootstrap 4

    Project Structure

    react-hooks-redux-crud-example-project-structure

    I'm gonna explain it briefly.

    • package.json contains main modules: , , , , , & .
    • is the container that has & navbar.
    • There are 3 pages: , , .
    • http-common.js initializes axios with HTTP base Url and headers.
    • has methods for sending HTTP requests to the Apis.
    • .env configures port for this React CRUD App.

    About Redux elements that we're gonna use:

    • actions folder contains the action creator (tutorials.js for CRUD operations and searching).
    • reducers folder contains the reducer (tutorials.js) which updates the application state corresponding to dispatched action.

    For step by step and Github, please visit:
    https://bezkoder.com/react-hooks-redux-crud/

    Using Redux-Toolkit:
    Redux-Toolkit CRUD example with React Hooks

    Further Reading

    Security:

    Related Posts:

    Serverless with Firebase:

    Fullstack:

    Dockerize:

    Sours: https://dev.to/tienbku/react-hooks-redux-crud-example-with-axios-and-rest-api-525i
    React Redux Hooks Tutorial for Beginners

    React-Redux Hooks: useSelector and useDispatch

    React Redux offers a set of Hooks as an alternative to the existing higher order component. These Hooks allow you to connect to the Redux store and dispatch actions without having to wrap your components in .

    This guide will cover how to implement the React-Redux Hooks, and , in your application.

    Begin by installing the following in your app:

    npm install reduxnpm install react-redux

    The examples in this guide will be referring to my repository:

    Here is a quick gif of the app’s functionality:

    There are two separate states, one for keeping track of the counter and one for keeping track of a logged-in user. We will have separate files to handle each state.

    Actions

    Let’s begin with defining the actions for the counter in . A couple of methods are necessary, and . We will export these two methods in an object.

    Similarly, let’s define the actions for the current user in , which will also have two methods, and , that will be exported in an object.

    To be organized, we import these two files under one location, the file within the folder. We create a variable and set it to an object that contains the imported actions which will be exported.

    Reducers

    Similar to the approach taken for the actions file structure, we create separate folder to hold the user and the counter reducers. Let’s start with the counter reducer, .

    A reducer function takes in two arguments, and the . State does not necessarily have to be set to an object. In this case, the default value of the state is set to an integer.

    As we defined earlier, an action returns an object that can contain two keys, and optionally a . Based on the action type, the value of the state will be changed. Keep in mind that a default case is necessary in the event that an action type is called that does not exist to prevent the app from breaking.

    For the current user reducer, , the state will be set to an empty object that will contain the keys and . Notice the difference in what is being returned between and . In all cases, the counter reducer returns an integer since its initial value was an integer. In the case of the current user reducer, an object is always returned.

    We need to combine these reducers into one. Under , let’s import the reducer files as well as :

    import {combineReducers} from 'redux'

    Combine reducers does what its name implies and combines the separate reducer files into one. It takes in one argument, an object that contains the reducer files. Now that our actions and reducers are set, let’s move on to implementing Redux in our app.

    In our under the folder, we will import the following:

    import {Provider} from 'react-redux';
    import {createStore} from 'redux'
    import rootReducer from './reducers'

    A Redux store will be created with the method . It takes in two arguments, the which is the file that combined our reducers and the Redux devtools extension.

    Finally, we wrap our component with the component from . The component will take in one prop, store which will be set to the from .

    We import the following hooks from react-redux, and . Before, we had to import from react-redux and wrap our components with it in order to map state to props and map dispatch to props.

    useSelector

    The equivalent of map state to props is . It takes in a function argument that returns the part of the state that you want. In this case, we have the following keys from state defined, and . We defined these earlier when combining reducers.

    const counter = useSelector(state => state.counter)
    // 1const currentUser = useSelector(state => state.currentUser)
    // {}

    Thus the variables and are set to the state defined from their respective reducers.

    useDispatch

    The equivalent of map dispatch to props is . We will invoke and store it to a variable, . Dispatch will work with the imported from the actions folder. For example, calls a with the following action, . User is defined as:

    const user = {name: "Rei"}

    Keep in mind, is an object with and as keys. Just as a refresher on the function defined in :

    const setUser = (userObj) => { return { type: "SET_USER", payload: userObj }}

    will return an object with and . Dispatch will take this object and look through the reducers that match the action type. In this particular case, it is located within folder.

    case "SET_USER": return { ...state, user: action.payload, loggedIn: true}

    And there you have it. The React-Redux hooks and are implemented in the React App. Compared to the alternative, the code is cleaner and more organized.

    Thank you for reading!

    Sours: https://levelup.gitconnected.com/react-redux-hooks-useselector-and-usedispatch-f7d8c7f75cdd

    Redux example react hooks

    React Hooks + Redux: CRUD example with Axios and Rest API

    In this tutorial, I will show you how to build a React Hooks + Redux CRUD Application example to consume Rest API, display and modify data with Router, Axios & Bootstrap.

    Security:
    – React Hooks: JWT Authentication (without Redux) example
    – React Hooks + Redux: JWT Authentication example

    Related Posts:
    – React CRUD example with Axios and Web API (using React Components)
    – React Hooks (without Redux) CRUD example with Axios and Web API
    – React Hooks File Upload example with Axios & Progress Bar
    – React Table example: CRUD App | react-table 7
    – React Form Validation with Hooks example

    Serverless with Firebase:
    – React Hooks + Firebase Realtime Database: CRUD App
    – React Hooks + Firestore example: CRUD app

    Contents

    Overview of React Hooks Redux CRUD example

    We will build a React Redux Tutorial Application with Rest API calls in that:

    • Each Tutorial has id, title, description, published status.
    • We can create, retrieve, update, delete Tutorials.
    • There is a Search bar for finding Tutorials by title.

    Here are screenshots of our React Redux CRUD Application.

    – Create a Tutorial:

    react-hooks-redux-crud-example-create-tutorial

    – Retrieve all Tutorials:

    react-hooks-redux-crud-example-retrieve-tutorial

    – Click on Edit button to update a Tutorial:

    react-hooks-redux-crud-example-retrieve-one-tutorial

    On this Page, you can:

    • change status to Published using Publish button
    • delete the item using Delete button
    • update the item details with Update button

    react-hooks-redux-crud-example-update-tutorial

    If you need Form Validation with React Hook Form 7, please visit:
    React Form Validation with Hooks example

    – Search Tutorials by title:

    react-hooks-redux-crud-example-search-tutorial

    – Check Redux State with Dev-tool:

    react-hooks-redux-crud-example-check-redux-state

    This React Client consumes the following Web API:

    MethodsUrlsActions
    POST/api/tutorialscreate new Tutorial
    GET/api/tutorialsretrieve all Tutorials
    GET/api/tutorials/:idretrieve a Tutorial by
    PUT/api/tutorials/:idupdate a Tutorial by
    DELETE/api/tutorials/:iddelete a Tutorial by
    DELETE/api/tutorialsdelete all Tutorials
    GET/api/tutorials?title=[keyword]find all Tutorials which title contains

    You can find step by step to build a Server like this in one of these posts:
    – Express, Sequelize & MySQL
    – Express, Sequelize & PostgreSQL
    – Express, Sequelize & SQL Server
    – Express & MongoDb
    – Spring Boot & MySQL
    – Spring Boot & PostgreSQL
    – Spring Boot & MongoDB
    – Spring Boot & SQL Server
    – Spring Boot & H2
    – Spring Boot & Cassandra
    – Spring Boot & Oracle
    – Django & MySQL
    – Django & PostgreSQL
    – Django & MongoDB

    React Hooks Redux CRUD Component Diagram with Router & Axios

    Now look at the React components that we’re gonna implement:

    react-hooks-redux-crud-example-components

    – The component is a container with React . It has that links to routes paths.

    – Three pages that dispatch actions to which uses to call Rest API:

    • gets and displays Tutorials.
    • has form for editing Tutorial’s details based on .
    • has form for submission new Tutorial.

    – uses to make HTTP requests and receive responses.

    React Hooks + Redux with API example

    This diagram shows how Redux elements work in our React Hooks Application:

    react-hooks-redux-crud-example-redux-store-architecture

    We’re gonna create Redux for storing data. Other React Components will work with the Store via dispatching an or getting value using React-Redux Hooks API.

    The will take the action and return new .

    Technology

    • React 17/16
    • react-redux 7.2.3
    • redux 4.0.5
    • redux-thunk 2.3.0
    • react-router-dom 5.2.0
    • axios 0.21.1
    • bootstrap 4

    Project Structure

    react-hooks-redux-crud-example-project-structure

    I’m gonna explain it briefly.

    package.json contains main modules: , , , , , & .
    – is the container that has & navbar.
    – There are 3 pages: , , .
    http-common.js initializes axios with HTTP base Url and headers.
    – has methods for sending HTTP requests to the Apis.
    .env configures port for this React CRUD App.

    About Redux elements that we’re gonna use:
    actions folder contains the action creator (tutorials.js for CRUD operations and searching).
    reducers folder contains the reducer (tutorials.js) which updates the application state corresponding to dispatched action.

    If you want to use Redux-Toolkit instead, please visit:
    Redux-Toolkit CRUD example with React Hooks

    Setup React.js Project

    Open cmd at the folder you want to save Project folder, run command:

    After the process is done. We create additional folders and files like the following tree:


    public

    src

    actions

    types.js

    tutorials.js (create/retrieve/update/delete actions)

    reducers

    index.js

    tutorials.js

    components

    AddTutorial.js

    Tutorial.js

    TutorialsList.js

    services

    TutorialService.js

    App.css

    App.js

    index.js

    store.js

    package.json


    Install Bootstrap to React Hooks Redux CRUD App

    Run command: .

    Open src/App.js and modify the code inside it as following-

    Add React Router to React Hooks Redux CRUD App

    – Run the command: .
    – Open src/App.js and wrap all UI elements by object.

    Add Navbar to React Hooks Redux CRUD App

    The component is the root container for our application, it will contain a inside above, and also, a object with several . Each points to a React Component.

    Now App.js looks like:

    Initialize Axios for React Hooks Redux CRUD HTTP Client

    Let’s install axios with command: .
    Under src folder, we create http-common.js file with following code:

    You can change the that depends on REST APIs url that your Server configures.

    For more details about ways to use Axios, please visit:
    Axios request: Get/Post/Put/Delete example

    Create Data Service

    In this step, we’re gonna create a service that uses axios object above to send HTTP requests.
    The service exports CRUD functions and finder method:

    • CREATE:
    • RETRIEVE: ,
    • UPDATE:
    • DELETE: ,
    • FINDER:

    services/TutorialService.js

    We call axios (imported as http) , , , method corresponding to HTTP Requests: GET, POST, PUT, DELETE to make CRUD Operations.

    Create Redux Actions

    We’re gonna create actions in src/actions folder:


    actions

    types.js

    tutorials.js (create/retrieve/update/delete actions)


    Action Types

    First we defined some string constant that indicates the type of action being performed.

    actions/type.js

    Actions Creator

    This is creator for actions related to tutorials. We’re gonna import to make asynchronous HTTP requests with trigger on the result.

    • calls the
    • dispatch

    • calls the
    • dispatch

    • calls the
    • dispatch

    • calls the
    • dispatch

    • calls the
    • dispatch

    • calls the
    • dispatch

    Some action creators return a for Components using them.

    actions/tutorials.js

    You can simplify import statement with:
    Absolute Import in React

    Create Redux Reducer

    There will be a reducer in src/reducers folder, the reducer updates the state corresponding to dispatched Redux actions.


    reducers

    index.js

    tutorials.js


    Tutorials Reducer

    The reducer will update state of the Redux store:
    reducers/tutorials.js

    Combine Reducers

    reducers/index.js

    Because we only have a single store in a Redux application. We use reducer composition instead of many stores to split data handling logic.

    For example, if you have Auth Reducer that manages authentication logic, you can use like following code:

    Create Redux Store

    This Store will bring Actions and Reducers together and hold the Application state.

    Now we need to install Redux, Thunk Middleware and Redux Devtool Extension.
    Run the command:

    In the previous section, we used to combine 2 reducers into one. Let’s import it, and pass it to :

    store.js

    Provide State to React Components

    We start by wrapping our entire application in a component to make the available to its child components.

    Open src/index.js

    Create React Components

    Now we’re gonna build 3 components corresponding to 3 Routes defined before.

    Add Object

    This component has a Form to submit new Tutorial with 2 fields: & .

    react-hooks-redux-crud-example-create-tutorial

    components/AddTutorial.js

    First, we define and set initial state: & .

    Next, we create function to track the values of the input and set that state for changes.

    We also have a function to get local state and send the POST request to the Web API. It dispatchs action with action creator with . This hook returns a reference to the function from the Redux store.

    For , we check the state, if it is true, we show Add button for creating new Tutorial again. Otherwise, a Form with Submit button will display.

    List of Objects

    This component has:

    • a search bar for finding Tutorials by title.
    • a tutorials array displayed as a list on the left.
    • a selected Tutorial which is shown on the right.

    react-hooks-redux-crud-example-retrieve-tutorial

    Beside global state , we also have following local state:

    • and

    We also need to use 3 action creators:

      To connect the Redux store with local Component state and props, we use and .

      When using with an inline selector above, a new instance of the selector is created whenever the component is rendered.

      Now we can work with state and dispatch actions like this:

      components/TutorialsList.js

      Let’s continue to implement UI elements:

      If you click on Edit button of any Tutorial, the app will direct you to Tutorial page.
      We use React Router for accessing that page with url: .

      Object details

      react-hooks-redux-crud-example-retrieve-one-tutorial

      This component will use method in the Effect Hook to get Tutorial by id in the URL.

      For update, delete the Tutorial, we work with following action creators:

        components/Tutorial.js

        And this is the code inside :

        Add CSS style for React Components

        Open src/App.css and write CSS code as following:

        Configure Port for React Redux CRUD with Web API

        Because most of HTTP Server use CORS configuration that accepts resource sharing retrictted to some sites or ports, so we also need to configure port for our App.

        In project folder, create .env file with following content:

        Now we’ve set our app running at port .

        Run React Hooks Redux CRUD App

        You can run our App with command: .
        If the process is successful, open Browser with Url: and check it.

        This React Client will work well with following back-end Rest APIs:
        – Express, Sequelize & MySQL
        – Express, Sequelize & PostgreSQL
        – Express, Sequelize & SQL Server
        – Express & MongoDb
        – Spring Boot & MySQL
        – Spring Boot & PostgreSQL
        – Spring Boot & MongoDB
        – Spring Boot & SQL Server
        – Spring Boot & H2
        – Spring Boot & Cassandra
        – Spring Boot & Oracle
        – Django & MySQL
        – Django & PostgreSQL
        – Django & MongoDB

        Conclusion

        Today we’ve built a React Hooks Redux CRUD example successfully with React Router & Axios. Now we can consume REST APIs, display, search and modify data with Redux Store in a clean way. I hope you can make API call (GET/POST/PUT/DELETE) in your project at ease.

        If you don’t want to use Redux:
        React Hooks (without Redux) CRUD example with Axios and Web API

        Implement Security:
        – React Hooks: JWT Authentication (without Redux) example
        – React Hooks + Redux: JWT Authentication example

        You can add Pagination Component:
        React Pagination using Hooks example

        react-pagination-hooks-material-ui-change-page

        Or Form Validation:
        React Form Validation with Hooks example

        Happy learning, see you again!

        Further Reading

        For more details about ways to use Axios, please visit:
        Axios request: Get/Post/Put/Delete example

        Fullstack:
        – Spring Boot + React Redux example: Build a CRUD App
        – React + Spring Boot + MySQL: CRUD example
        – React + Spring Boot + PostgreSQL: CRUD example
        – React + Spring Boot + MongoDB: CRUD example
        – React + Node.js + Express + MySQL: CRUD example
        – React Redux + Node.js + Express + MySQL: CRUD example
        – React + Node.js + Express + PostgreSQL example
        – React + Node.js + Express + MongoDB example
        – React + Django + Rest Framework example

        Source Code

        You can find the complete source code for this example on Github.

        Using Redux-Toolkit instead:
        Redux-Toolkit CRUD example with React Hooks

        Sours: https://www.bezkoder.com/react-hooks-redux-crud/
        React Redux (with Hooks) Crash Course - 2021

        react-redux with hooks is here!

        In an alpha version.

        The hottest thing in the React community right now is hooks. And it’s pretty sweet. It makes the code much compact and easy to read and work with.

        If you use Redux with React you’re familiar with the function. This is a higher-order component that injects props to the React components with actions and data from the store.

        But now that we are in 2019 you can use hooks for this instead!

        A quick translation of connect()() to hooks

        The official docs on this topic are extensive and in-depth. It covers many edge cases. This is a TLDR; version of the docs. I’ll only show you the happy-path. I’ll take you step-by-step and refactor an old to using the new hooks.

        First an example with the old connect function

        Ok so we have the function that looks something like this

        The and function for a simple increase counter app looks like this:

        I assume you already know how it works, if not, theseposts might help.

        An (almost) complete example of a React component using our connect function looks like this:

        The maps from the Redux state to the prop that is injected into the React component.

        The maps an action creator to the prop that is injected into the React component.

        What is not visible in this example is that the root component of the app must be wrapped inside the component.

        Now let’s translate this to hooks!

        First you must install the latest alpha version of . It’s the version and later that contains hooks.

        The code that uses hooks looks like this:

        We use two hooks: and . We use to get the data out from the store and use it in the component, and we use to be able to dispatch action creators. You don’t have to use bothand, you can only use one of them if you want.

        Just as with , we must wrap the root component with for this to work.

        useSelector

        In this example the is very similar to the old - with one exception: it returns a value instead of an object. This is useful if your React component cares about one value from the store, like in this example.

        In the old function we had to return an object even if we only wanted to use one value. We no longer have this limitation with hooks.

        can however still return object if you need to extract many values from the store:

        useDispatch

        We no longer have access to something similar to . The way we now dispatch actions is with calling and passing in an action. We get the by calling hook.

        And we dispatch it by calling passing in the return value from the action creator

        More react-redux hooks

        That’s it. I haven’t dig into the details, edge cases, and performance optimizations because the docs do that just perfectly: react-redux hooks docs. In the docs you can also learn about more hooks if you need more fine-grained control like .


        tags:
        Sours: https://blog.jakoblind.no/react-redux-hooks/

        You will also like:

        Hooks

        React's new "hooks" APIs give function components the ability to use local component state, execute side effects, and more. React also lets us write custom hooks, which let us extract reusable hooks to add our own behavior on top of React's built-in hooks.

        React Redux includes its own custom hook APIs, which allow your React components to subscribe to the Redux store and dispatch actions.

        tip

        We recommend using the React-Redux hooks API as the default approach in your React components.

        The existing API still works and will continue to be supported, but the hooks API is simpler and works better with TypeScript.

        These hooks were first added in v7.1.0.

        Using Hooks in a React Redux App​

        As with , you should start by wrapping your entire application in a component to make the store available throughout the component tree:

        From there, you may import any of the listed React Redux hooks APIs and use them within your function components.

        Allows you to extract data from the Redux store state, using a selector function.

        info

        The selector function should be pure since it is potentially executed multiple times and at arbitrary points in time.

        The selector is approximately equivalent to the argument to conceptually. The selector will be called with the entire Redux store state as its only argument. The selector will be run whenever the function component renders (unless its reference hasn't changed since a previous render of the component so that a cached result can be returned by the hook without re-running the selector). will also subscribe to the Redux store, and run your selector whenever an action is dispatched.

        However, there are some differences between the selectors passed to and a function:

        • The selector may return any value as a result, not just an object. The return value of the selector will be used as the return value of the hook.
        • When an action is dispatched, will do a reference comparison of the previous selector result value and the current result value. If they are different, the component will be forced to re-render. If they are the same, the component will not re-render.
        • The selector function does not receive an argument. However, props can be used through closure (see the examples below) or by using a curried selector.
        • Extra care must be taken when using memoizing selectors (see examples below for more details).
        • uses strict reference equality checks by default, not shallow equality (see the following section for more details).

        info

        There are potential edge cases with using props in selectors that may cause issues. See the Usage Warnings section of this page for further details.

        You may call multiple times within a single function component. Each call to creates an individual subscription to the Redux store. Because of the React update batching behavior used in React Redux v7, a dispatched action that causes multiple s in the same component to return new values should only result in a single re-render.

        Equality Comparisons and Updates​

        When the function component renders, the provided selector function will be called and its result will be returned from the hook. (A cached result may be returned by the hook without re-running the selector if it's the same function reference as on a previous render of the component.)

        However, when an action is dispatched to the Redux store, only forces a re-render if the selector result appears to be different than the last result. As of v7.1.0-alpha.5, the default comparison is a strict reference comparison. This is different than , which uses shallow equality checks on the results of calls to determine if re-rendering is needed. This has several implications on how you should use .

        With , all individual fields were returned in a combined object. It didn't matter if the return object was a new reference or not - just compared the individual fields. With , returning a new object every time will always force a re-render by default. If you want to retrieve multiple values from the store, you can:

        • Call multiple times, with each call returning a single field value
        • Use Reselect or a similar library to create a memoized selector that returns multiple values in one object, but only returns a new object when one of the values has changed.
        • Use the function from React-Redux as the argument to , like:

        The optional comparison function also enables using something like Lodash's or Immutable.js's comparison capabilities.

        Examples​

        Basic usage:

        Using props via closure to determine what to extract:

        Using memoizing selectors​

        When using with an inline selector as shown above, a new instance of the selector is created whenever the component is rendered. This works as long as the selector does not maintain any state. However, memoizing selectors (e.g. created via from ) do have internal state, and therefore care must be taken when using them. Below you can find typical usage scenarios for memoizing selectors.

        When the selector does only depend on the state, simply ensure that it is declared outside of the component so that the same selector instance is used for each render:

        The same is true if the selector depends on the component's props, but will only ever be used in a single instance of a single component:

        However, when the selector is used in multiple component instances and depends on the component's props, you need to ensure that each component instance gets its own selector instance (see here for a more thorough explanation of why this is necessary):

        This hook returns a reference to the function from the Redux store. You may use it to dispatch actions as needed.

        Examples​

        When passing a callback using to a child component, you may sometimes want to memoize it with . If the child component is trying to optimize render behavior using or similar, this avoids unnecessary rendering of child components due to the changed callback reference.

        info

        The function reference will be stable as long as the same store instance is being passed to the . Normally, that store instance never changes in an application.

        However, the React hooks lint rules do not know that should be stable, and will warn that the variable should be added to dependency arrays for and . The simplest solution is to do just that:

        This hook returns a reference to the same Redux store that was passed in to the component.

        This hook should probably not be used frequently. Prefer as your primary choice. However, this may be useful for less common scenarios that do require access to the store, such as replacing reducers.

        Examples​

        Custom context​

        The component allows you to specify an alternate context via the prop. This is useful if you're building a complex reusable component, and you don't want your store to collide with any Redux store your consumers' applications might use.

        To access an alternate context via the hooks API, use the hook creator functions:

        Usage Warnings​

        Stale Props and "Zombie Children"​

        info

        The React-Redux hooks API has been production-ready since we released it in v7.1.0, and we recommend using the hooks API as the default approach in your components. However, there are a couple of edge cases that can occur, and we're documenting those so that you can be aware of them.

        One of the most difficult aspects of React Redux's implementation is ensuring that if your function is defined as , it will be called with the "latest" props every time. Up through version 4, there were recurring bugs reported involving edge case situations, such as errors thrown from a function for a list item whose data had just been deleted.

        Starting with version 5, React Redux has attempted to guarantee that consistency with . In version 7, that is implemented using a custom class internally in , which forms a nested hierarchy. This ensures that connected components lower in the tree will only receive store update notifications once the nearest connected ancestor has been updated. However, this relies on each instance overriding part of the internal React context, supplying its own unique instance to form that nesting, and rendering the with that new context value.

        With hooks, there is no way to render a context provider, which means there's also no nested hierarchy of subscriptions. Because of this, the "stale props" and "zombie child" issues may potentially re-occur in an app that relies on using hooks instead of .

        Specifically, "stale props" means any case where:

        • a selector function relies on this component's props to extract data
        • a parent component would re-render and pass down new props as a result of an action
        • but this component's selector function executes before this component has had a chance to re-render with those new props

        Depending on what props were used and what the current store state is, this may result in incorrect data being returned from the selector, or even an error being thrown.

        "Zombie child" refers specifically to the case where:

        • Multiple nested connected components are mounted in a first pass, causing a child component to subscribe to the store before its parent
        • An action is dispatched that deletes data from the store, such as a todo item
        • The parent component would stop rendering that child as a result
        • However, because the child subscribed first, its subscription runs before the parent stops rendering it. When it reads a value from the store based on props, that data no longer exists, and if the extraction logic is not careful, this may result in an error being thrown.

        tries to deal with this by catching all errors that are thrown when the selector is executed due to a store update (but not when it is executed during rendering). When an error occurs, the component will be forced to render, at which point the selector is executed again. This works as long as the selector is a pure function and you do not depend on the selector throwing errors.

        If you prefer to deal with this issue yourself, here are some possible options for avoiding these problems altogether with :

        • Don't rely on props in your selector function for extracting data
        • In cases where you do rely on props in your selector function and those props may change over time, or the data you're extracting may be based on items that can be deleted, try writing the selector functions defensively. Don't just reach straight into - read first, and verify that it exists before trying to read .
        • Because adds the necessary to the context provider and delays evaluating child subscriptions until the connected component has re-rendered, putting a connected component in the component tree just above the component using will prevent these issues as long as the connected component gets re-rendered due to the same store update as the hooks component.

        info

        For a longer description of these scenarios, see:

        Performance​

        As mentioned earlier, by default will do a reference equality comparison of the selected value when running the selector function after an action is dispatched, and will only cause the component to re-render if the selected value changed. However, unlike , does not prevent the component from re-rendering due to its parent re-rendering, even if the component's props did not change.

        If further performance optimizations are necessary, you may consider wrapping your function component in :

        Hooks Recipes​

        We've pared down our hooks API from the original alpha release, focusing on a more minimal set of API primitives. However, you may still wish to use some of the approaches we tried in your own apps. These examples should be ready to copy and paste into your own codebase.

        Recipe: ​

        This hook was in our original alpha release, but removed in , based on Dan Abramov's suggestion. That suggestion was based on "binding action creators" not being as useful in a hooks-based use case, and causing too much conceptual overhead and syntactic complexity.

        You should probably prefer to call the hook in your components to retrieve a reference to , and manually call in callbacks and effects as needed. You may also use the Redux function in your own code to bind action creators, or "manually" bind them like .

        However, if you'd like to still use this hook yourself, here's a copy-pastable version that supports passing in action creators as a single function, an array, or an object.

        Recipe: ​

        There are some architectural trade offs to take into consideration when deciding whether to use hooks or not. Mark Erikson summarizes these nicely in his two blog posts Thoughts on React Hooks, Redux, and Separation of Concerns and Hooks, HOCs, and Tradeoffs.

        Sours: https://react-redux.js.org/api/hooks


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