Cách Sử Dụng XState Với React

Trong một thời gian dài, Redux là cách để thực hiện quản lý trạng thái trong một ứng dụng React. Dựa trên kiến trúc Flux , được Facebook phổ biến, nó bổ sung cho các thành phần chế độ xem có thể kết hợp của React bằng cách sử dụng luồng dữ liệu một chiều.

Redux hoạt động tốt, nhưng cảm giác là bạn viết quá nhiều mã cho vấn đề bạn đang cố gắng giải quyết. Và, khi bạn cần làm việc với các hoạt động không đồng bộ, như lệnh gọi API, bạn cần sử dụng thứ gì đó phức tạp hơn như react-thunkhoặc react-saga. Mã cảm thấy phức tạp không cần thiết.

Trong những năm qua, mọi người đã đưa ra các lựa chọn thay thế như MobX , Recoil , Immer , XState và nhiều loại khác. Một số người không sử dụng bất kỳ cái nào trong số chúng và thay thế Redux bằng sự kết hợp của các hook (useContext + useState / useReducer)

XState có một chút khác biệt so với phần còn lại, trạng thái được quản lý bởi một máy trạng thái hữu hạn. Như chúng ta đã thấy trong một bài viết trước , điều này có nghĩa là bạn có thể tránh các tình huống "trạng thái xấu" với XState. Không có lựa chọn thay thế nào khác ngăn chặn trạng thái xấu.

Để xem cách XState hoạt động với React, chúng ta sẽ xem xét một ví dụ phức tạp, một máy XState cho WebSocket cung cấp các đơn đặt hàng tiền điện tử ( websocket của cryptofacilities.com: wss: // www.cryptofacilities.com/ws/v1 ). Tại sao một ví dụ phức tạp? Bởi vì đây là nơi XState tỏa sáng khi một số hành động nhất định chỉ khả dụng ở một số trạng thái nhất định.

Để lấy dữ liệu từ websocket, chúng ta cần thực hiện các bước sau:

Khởi tạo websocket

const socket = new WebSocket('https://www.cryptofacilities.com/');
const connectedHandler = () => { console.log('Connected')};

socket.addEventListener('open', connectedHandler);         

const messageHandler = (e) => { console.log('Message received', e.data)};
socket.addEventListener('message', messageHandler);

Đăng ký dữ liệu tiền điện tử cụ thể

const subscribeEvent = {
  "event": "subscribe",
  "feed": "book_ui_1",
  "product_ids": ["PI_XBTUSD"]
}
socket.send(JSON.stringify(subscribeEvent));

Chờ websocket xác nhận đăng ký


// update the messageHandler to handle subscribed events
const messageHandler = (e) => { 
  console.log('Message received', e.data);
  
   if(/"event"/g.test(e.data)) {
    if(/"subscribed"/g.test(e.data)) {
      console.log('Subscribed');
    }
  }
};

Nhận dữ liệu ban đầu từ websocket dưới dạng ảnh chụp nhanh

// update the messageHandler to handle snapshots
const messageHandler = (e) => { 
  console.log('Message received', e.data);
  
  if(/"event"/g.test(e.data)) {
    if(/"subscribed"/g.test(e.data)) {
      console.log('Subscribed');
    }
  }
  else {
    if(/snapshot/g.test(data.feed)) {
      console.log('Snapshot received');
    }  
  }
};

Nhận các thay đổi dữ liệu (delta) từ websocket

// update the messageHandler to handle deltas
const messageHandler = (e) => { 
  console.log('Message received', e.data);
  
  if(/"event"/g.test(e.data)) {
    if(/"subscribed"/g.test(e.data)) {
      console.log('Subscribed');
    }
  }
  else {
    if(/snapshot/g.test(data.feed)) {
      console.log('Snapshot received');
    }  
    else {
      console.log('Deltas received');
    }
  }
};

Hủy đăng ký nhận dữ liệu tiền điện tử


// send unsubscribe event
const unsubscribeEvent = {
  "event": "unsubscribe",
  "feed": "book_ui_1",
  "product_ids": ["PI_XBTUSD"]
}
socket.send(JSON.stringify(unsubscribeEvent));

// handle unsubscribe confirmation
const messageHandler = (e) => { 
  console.log('Message received', e.data);
  
  if(/"event"/g.test(e.data)) {
    if(/"subscribed"/g.test(e.data)) {
      console.log('Subscribed');
    } else if(/"unsubscribed"/g.test(e.data)) {
      console.log('Unsubscribed');
    }  
  }
  else {
    if(/snapshot/g.test(data.feed)) {
      console.log('Snapshot received');
    }  
    else {
      console.log('Deltas received');
    }
  }
};

Đăng ký dữ liệu tiền điện tử khác

const subscribeEvent = {
  "event": "subscribe",
  "feed": "book_ui_1",
  "product_ids": ["PI_ETHUSD"]
}
socket.send(JSON.stringify(subscribeEvent));

Để sử dụng đúng websocket, chúng ta cần có trạng thái phù hợp:

chúng tôi không thể gửi sự kiện nếu websocket không được kết nối
chúng tôi không thể đăng ký một đồng xu nếu chúng tôi đã đăng ký một đồng xu khác,
chúng tôi cần đợi để hủy đăng ký trước khi chúng tôi có thể đăng ký lại

Một máy cho một Websocket

let socket;

const wsMachine = Machine({
  id: 'websocket',
  initial: 'idle',
  context: {
    initialized: false,
    forcePause: false,
    feed: 'PI_XBTUSD',
    data: undefined,
    error: undefined,
  },
  states: {
    idle: {
      on: { 
        CONNECT: 'pending' 
      }
    },
    pending: {
      invoke: {
        id:'connectWebsocket',
        src: () => (callback) => {
          try {
            socket = new WebSocket('wss://www.cryptofacilities.com/ws/v1');

            const connectedHandler = () => callback('CONNECTED');
            socket.addEventListener('open', connectedHandler);            

            return () => {
              socket?.removeEventListener('open', connectedHandler);
            };  
          } catch(err) {
            callback({ type: 'FAILURE', error: err} );
          }
        }
      },
      on: {
         CONNECTED: {
           target: 'connected',             
           cond: (context) => !!socket && !!context.feed,
           actions: assign({ error: (context, event) => undefined })
         },  
         FAILURE: {
          target: 'idle',
          actions: assign({ error: (context, event) => event.error })
         }  
      }
    },
    connected: {
      id:'connection',
      invoke: {
        src: () => (callback) => {
          const messageHandler = (e) => {
              if(/"event"/g.test(e.data)) {
                if(/"unsubscribed"/g.test(e.data)) {
                  callback('PAUSED');                
                }
                else if(/"subscribed"/g.test(e.data)) {
                  callback('STARTED');
                }
              }
              else {
                if(/"snapshot"/g.test(e.data)) {
                  console.log('Handle snapshot');
                  callback({ type: 'RECEIVE', data: e.data} );
                } else {
                  console.log('Handle deltas');                  
                  // TODO merge current data with deltas
                  callback({ type: 'RECEIVE', data: e.data} );
                }
              }
          };              
          socket.addEventListener('message', messageHandler);    

          return () => {
            socket.removeEventListener('message', messageHandler);    
          };
        }
      },     
      initial: 'paused',
      states: {          
        starting: {
          on: {
            STARTED: {
              target:'started'
            }
          }
        },
        pausing :{
          on: {
            PAUSED: {
              target: 'paused',
            }, 
          }
        }, 
        started: {         
          on : {
            PAUSE: {
              target: 'pausing',
              actions: [
                assign({ forcePause: (context, event) => event.forced }),
                (context) => {
                  const unsubscribeEvent = {
                    "event": "unsubscribe",
                    "feed": "book_ui_1",
                    "product_ids": [`${context.feed}`]
                  }
                  socket?.send(JSON.stringify(unsubscribeEvent));
                }
              ]
            },           
            RECEIVE: {
              actions: assign({ data: (context, event) => event.data })
            },  
          },       
        },     
        paused: {          
          on: {
            START: {
              target: 'starting',
              actions: [
                (context) => {
                  const subscribeEvent = {
                    "event": "subscribe",
                    "feed": "book_ui_1",
                    "product_ids": [`${context.feed}`]
                  }
                  socket?.send(JSON.stringify(subscribeEvent));
                },
                assign({ initialized : (context, event) =>  true })
              ]
            },
            SWITCH: {
              actions: [
                assign({ feed : (context, event) =>  event.feed || context.feed }),
                assign({ data : (context, event) => {                  
                  return undefined;
                }}),                
              ]
            },
            CLOSE: {
              target: '#websocket.idle',
              actions: () => {
                socket?.close();            
              }
            }
          }
        }        
      }      
    }
  }
})

Mẹo: Sao chép mã trên trong trình hiển thị XState để xem nó hoạt động.

Ban đầu, máy không hoạt động và việc đầu tiên chúng ta cần làm là kết nối máy. Sự kiện duy nhất có sẵn là CONNECT, không có gì khác có sẵn. Ngay cả khi bằng cách nào đó, một sự kiện như TẠM DỪNG hoặc BẮT ĐẦU được nhận, không có gì xảy ra

Sau khi máy được kết nối, máy sẽ ở trạng thái tạm dừng. Tại đây có sẵn một số sự kiện: BẮT ĐẦU - để khởi động máy, CHUYỂN ĐỔI - để chuyển sang đồng xu khác và ĐÓNG - để đóng websocket.

Chúng ta cần khởi động máy để máy có thể nhận dữ liệu từ websocket.

Sử dụng Máy trong React

Đầu tiên, chúng tôi cần thêm các thư viện XState và XState React vào dự án của bạn:

npm i xstate @xstate-react

Sau đó, tạo máy trong một tệp giống như websocket-machine.js(lưu ý rằng Machinenó không được dùng để ủng hộ createMachine)

import { createMachine } from 'xstate';

export const wsMachine = createMachine({
  ... 
}

Chúng ta cần tạo một ngữ cảnh React sử dụng máy để tạo một phiên bản của máy như một dịch vụ:

import React, { createContext } from 'react';
import { useInterpret } from '@xstate/react';
import machine from './websocket-machine';

export const MachineContext = createContext(null);

export const MachineProvider = (props) => {
  const machineService = useInterpret(machine);

  return (
    <MachineContext.Provider value={ machineService }>
      {props.children}
    </MachineContext.Provider>
  );
};

Sử dụng ngữ cảnh trong phần của ứng dụng sử dụng máy:

import MachineProvider from './machine-context';

<MachineProvider>
  <OrderbookDisplay/>   
</MachineProvider>

Cuối cùng, trong các thành phần là con của MachineProvider, chúng ta có thể sử dụng machineService:

import React, { useContext } from 'react';
import { MachineContext } from './machine-context';

// machine data selector
const dataSelector = state => state.context.data;

const OrderbookDisplay = () => {
  // get the service from context
  const machineService = useContext(MachineContext);
  // get context data
  const data = useSelector(machineService, dataSelector) ;

  return <div>{JSON.stringify(data)}</div>  
}

export default OrderbookDisplay;

Bối cảnh máy chứa nhiều thứ khác nhau, nhưng nếu bạn chỉ cần một phần của nó, thì bạn nên sử dụng bộ chọn để chỉ lấy phần ngữ cảnh bạn cần. Nếu không, khi các phần khác cập nhật (ví dụ: nguồn cấp dữ liệu, lỗi, v.v.), thành phần của bạn sẽ làm mới một cách không cần thiết.

Sự kết luận

Bạn có thể sử dụng XState với React, thậm chí bạn có thể chỉ sử dụng nó cho các phần của trạng thái quan trọng để làm đúng. Đối với tôi, XState trông giống như ít mã hơn Redux và có quản lý trạng thái mạnh mẽ hơn.

Việc tạo ra máy XState là phần khó nhất. Cần một chút thử và sai để tạo ra một cái hoàn hảo bao gồm mọi góc độ. Nhưng một khi bạn có nó, bạn có thể dựa vào nó.

Nguồn: https://www.raresportan.com/xtate-and-react/

#react

What is GEEK

Buddha Community

Autumn Blick

1598839687

How native is React Native? | React Native vs Native App Development

If you are undertaking a mobile app development for your start-up or enterprise, you are likely wondering whether to use React Native. As a popular development framework, React Native helps you to develop near-native mobile apps. However, you are probably also wondering how close you can get to a native app by using React Native. How native is React Native?

In the article, we discuss the similarities between native mobile development and development using React Native. We also touch upon where they differ and how to bridge the gaps. Read on.

A brief introduction to React Native

Let’s briefly set the context first. We will briefly touch upon what React Native is and how it differs from earlier hybrid frameworks.

React Native is a popular JavaScript framework that Facebook has created. You can use this open-source framework to code natively rendering Android and iOS mobile apps. You can use it to develop web apps too.

Facebook has developed React Native based on React, its JavaScript library. The first release of React Native came in March 2015. At the time of writing this article, the latest stable release of React Native is 0.62.0, and it was released in March 2020.

Although relatively new, React Native has acquired a high degree of popularity. The “Stack Overflow Developer Survey 2019” report identifies it as the 8th most loved framework. Facebook, Walmart, and Bloomberg are some of the top companies that use React Native.

The popularity of React Native comes from its advantages. Some of its advantages are as follows:

Performance: It delivers optimal performance.
Cross-platform development: You can develop both Android and iOS apps with it. The reuse of code expedites development and reduces costs.
UI design: React Native enables you to design simple and responsive UI for your mobile app.
3rd party plugins: This framework supports 3rd party plugins.
Developer community: A vibrant community of developers support React Native.

Why React Native is fundamentally different from earlier hybrid frameworks

Are you wondering whether React Native is just another of those hybrid frameworks like Ionic or Cordova? It’s not! React Native is fundamentally different from these earlier hybrid frameworks.

React Native is very close to native. Consider the following aspects as described on the React Native website:

Access to many native platforms features: The primitives of React Native render to native platform UI. This means that your React Native app will use many native platform APIs as native apps would do.
Near-native user experience: React Native provides several native components, and these are platform agnostic.
The ease of accessing native APIs: React Native uses a declarative UI paradigm. This enables React Native to interact easily with native platform APIs since React Native wraps existing native code.

Due to these factors, React Native offers many more advantages compared to those earlier hybrid frameworks. We now review them.

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Mathew Rini

1615544450

How to Select and Hire the Best React JS and React Native Developers?

Since March 2020 reached 556 million monthly downloads have increased, It shows that React JS has been steadily growing. React.js also provides a desirable amount of pliancy and efficiency for developing innovative solutions with interactive user interfaces. It’s no surprise that an increasing number of businesses are adopting this technology. How do you select and recruit React.js developers who will propel your project forward? How much does a React developer make? We’ll bring you here all the details you need.

What is React.js?

Facebook built and maintains React.js, an open-source JavaScript library for designing development tools. React.js is used to create single-page applications (SPAs) that can be used in conjunction with React Native to develop native cross-platform apps.

React vs React Native

React Native is a platform that uses a collection of mobile-specific components provided by the React kit, while React.js is a JavaScript-based library.
React.js and React Native have similar syntax and workflows, but their implementation is quite different.
React Native is designed to create native mobile apps that are distinct from those created in Objective-C or Java. React, on the other hand, can be used to develop web apps, hybrid and mobile & desktop applications.
React Native, in essence, takes the same conceptual UI cornerstones as standard iOS and Android apps and assembles them using React.js syntax to create a rich mobile experience.

What is the Average React Developer Salary?

In the United States, the average React developer salary is $94,205 a year, or $30-$48 per hour, This is one of the highest among JavaScript developers. The starting salary for junior React.js developers is $60,510 per year, rising to $112,480 for senior roles.

* React.js Developer Salary by Country

United States- $120,000
Canada - $110,000
United Kingdom - $71,820
The Netherlands $49,095
Spain - $35,423.00
France - $44,284
Ukraine - $28,990
India - $9,843
Sweden - $55,173
Singapore - $43,801

In context of software developer wage rates, the United States continues to lead. In high-tech cities like San Francisco and New York, average React developer salaries will hit $98K and $114per year, overall.

However, the need for React.js and React Native developer is outpacing local labour markets. As a result, many businesses have difficulty locating and recruiting them locally.

It’s no surprise that for US and European companies looking for professional and budget engineers, offshore regions like India are becoming especially interesting. This area has a large number of app development companies, a good rate with quality, and a good pool of React.js front-end developers.

As per Linkedin, the country’s IT industry employs over a million React specialists. Furthermore, for the same or less money than hiring a React.js programmer locally, you may recruit someone with much expertise and a broader technical stack.

How to Hire React.js Developers?

Conduct thorough candidate research, including portfolios and areas of expertise.
Before you sit down with your interviewing panel, do some homework.
Examine the final outcome and hire the ideal candidate.

Why is React.js Popular?

React is a very strong framework. React.js makes use of a powerful synchronization method known as Virtual DOM, which compares the current page architecture to the expected page architecture and updates the appropriate components as long as the user input.

React is scalable. it utilises a single language, For server-client side, and mobile platform.

React is steady.React.js is completely adaptable, which means it seldom, if ever, updates the user interface. This enables legacy projects to be updated to the most new edition of React.js without having to change the codebase or make a few small changes.

React is adaptable. It can be conveniently paired with various state administrators (e.g., Redux, Flux, Alt or Reflux) and can be used to implement a number of architectural patterns.

Is there a market for React.js programmers?
The need for React.js developers is rising at an unparalleled rate. React.js is currently used by over one million websites around the world. React is used by Fortune 400+ businesses and popular companies such as Facebook, Twitter, Glassdoor and Cloudflare.

Final thoughts:

As you’ve seen, locating and Hire React js Developer and Hire React Native developer is a difficult challenge. You will have less challenges selecting the correct fit for your projects if you identify growing offshore locations (e.g. India) and take into consideration the details above.

If you want to make this process easier, You can visit our website for more, or else to write a email, we’ll help you to finding top rated React.js and React Native developers easier and with strives to create this operation

#hire-react-js-developer #hire-react-native-developer #react #react-native #react-js #hire-react-js-programmer

Franz Becker

1651604400

React Starter Kit: Build Web Apps with React, Relay and GraphQL.

React Starter Kit — "isomorphic" web app boilerplate

React Starter Kit is an opinionated boilerplate for web development built on top of Node.js, Express, GraphQL and React, containing modern web development tools such as Webpack, Babel and Browsersync. Helping you to stay productive following the best practices. A solid starting point for both professionals and newcomers to the industry.

See getting started guide, demo, docs, roadmap | Join #react-starter-kit chat room on Gitter | Visit our sponsors:

Hiring

Getting Started

Follow the getting started guide to download and run the project (Node.js >= 8.16.2)
Check the code recipes used in this boilerplate, or share yours

Customization

The master branch of React Starter Kit doesn't include a Flux implementation or any other advanced integrations. Nevertheless, we have some integrations available to you in feature branches that you can use either as a reference or merge into your project:

feature/redux (PR) — isomorphic Redux by Pavel Lang (see how to integrate Redux) (based on master)
feature/apollo (PR) — isomorphic Apollo Client by Pavel Lang (see Tracking PR #1147) (based on feature/redux)
feature/react-intl (PR) — isomorphic Redux and React Intl by Pavel Lang (see how to integrate React Intl) (based on feature/apollo)
feature/apollo-pure (PR) — Apollo devtools and TypeScript integration by piglovesyou (based on master)

You can see status of most reasonable merge combination as PRs labeled as TRACKING

If you think that any of these features should be on master, or vice versa, some features should removed from the master branch, please let us know. We love your feedback!

Comparison

	React Starter Kit	React Static Boilerplate	ASP.NET Core Starter Kit
App type	Isomorphic (universal)	Single-page application	Single-page application
Frontend
Language	JavaScript (ES2015+, JSX)	JavaScript (ES2015+, JSX)	JavaScript (ES2015+, JSX)
Libraries	React, History, Universal Router	React, History, Redux	React, History, Redux
Routes	Imperative (functional)	Declarative	Declarative, cross-stack
Backend
Language	JavaScript (ES2015+, JSX)	n/a	C#, F#
Libraries	Node.js, Express, Sequelize, GraphQL	n/a	ASP.NET Core, EF Core, ASP.NET Identity
SSR	Yes	n/a	n/a
Data API	GraphQL	n/a	Web API

Backers

♥ React Starter Kit? Help us keep it alive by donating funds to cover project expenses via OpenCollective or Bountysource!

lehneres Tarkan Anlar Morten Olsen Adam David Ernst Zane Hitchcox

How to Contribute

Anyone and everyone is welcome to contribute to this project. The best way to start is by checking our open issues, submit a new issue or feature request, participate in discussions, upvote or downvote the issues you like or dislike, send pull requests.

Learn More

Related Projects

GraphQL Starter Kit — Boilerplate for building data APIs with Node.js, JavaScript (via Babel) and GraphQL
Membership Database — SQL schema boilerplate for user accounts, profiles, roles, and auth claims
Babel Starter Kit — Boilerplate for authoring JavaScript/React.js libraries

Support

#react-starter-kit on Stack Overflow — Questions and answers
#react-starter-kit on Gitter — Watch announcements, share ideas and feedback
GitHub issues, or Scrum board — File issues, send feature requests
appear.in/react — Open hours! Exchange ideas and experiences (React, GraphQL, startups and pet projects)
@koistya on Codementor, or Skype — Private consulting

License

Author: kriasoft
Source Code: https://github.com/kriasoft/react-starter-kit
License: MIT License

#graphql #react

Juned Ghanchi

1621573085

React Native App Developers India, React Native App Development Company

Expand your user base by using react-native apps developed by our expert team for various platforms like Android, Android TV, iOS, macOS, tvOS, the Web, Windows, and UWP.

We help businesses to scale up the process and achieve greater performance by providing the best react native app development services. Our skilled and experienced team’s apps have delivered all the expected results for our clients across the world.

To achieve growth for your business, hire react native app developers in India. You can count on us for all the technical services and support.

#react native app development company india #react native app developers india #hire react native developers india #react native app development company #react native app developers #hire react native developers

Abhishek Jaiswal

1607768450

What are hooks in React JS? - INFO AT ONE

In this article, you will learn what are hooks in React JS? and when to use react hooks? React JS is developed by Facebook in the year 2013. There are many students and the new developers who have confusion between react and hooks in react. Well, it is not different, react is a programming language and hooks is a function which is used in react programming language.
Read More:- https://infoatone.com/what-are-hooks-in-react-js/

#react #hooks in react #react hooks example #react js projects for beginners #what are hooks in react js? #when to use react hooks