Understand to Use Portal and Error Boundary in React

In this article, we will learn about React Portal and Error Boundary and how it can be used in React.

Portal

A React Portal is a way of binding an element outside of its component hierarchy, in a separate component. The name Portal represents that an element can be set anywhere in the DOM tree that’s outside of the normal React components tree. The concept of Portal is added after version 16.0 in React.

React provides an API to create portal named ReactDOM.createPortal() that accepts 2 parameters, the first parameter is an element which needs to be rendered and the second element is the DOM element in which it needs to be rendered. Portals are mostly used for implementing, Tooltip, Modals, Global message notifications, hovercards, chat widgets, and Floating menus. For Portal, we can return strings, numbers, components, React portals or an array of children.

Event Bubbling through React Portals

As React portal can be anywhere outside of DOM tree but it will act like a React child in all other ways, despite the fact that a child is a portal, it will still exist in the React tree regardless of its position in the DOM tree. So, if we want to trigger any event from the Portal, it will propagate to ancestors in the containing tree, even if those elements are not ancestors of the DOM tree.

Let’s look at the demo that will display tooltip using Portal.

import React, { Component } from 'react'    
    
class Tooltip extends Component {    
  constructor(props) {    
    super(props)    
    this.state = { hover: false }    
  }    
      
  handleMouseIn() {    
    this.setState({ hover: true })    
  }    
      
  handleMouseOut() {    
    this.setState({ hover: false })    
  }    
      
  render() {    
    const tooltipStyle = {    
      display: this.state.hover ? 'block' : 'none'    
    }    
        
    return (    
    
      <div>    
        <div onMouseOver={this.handleMouseIn.bind(this)} onMouseOut={this.handleMouseOut.bind(this)}>on hover here we will show the tooltip</div>    
        <div>    
          <div style={tooltipStyle}>this is the tooltip!!</div>    
        </div>    
      </div>    
    );    
  }    
}    
    
export default Tooltip     

Now, use the Tooltip component in the App component.

import React from 'react';    
import logo from './logo.svg';    
import './App.css';    
import Tooltip from "./components/Tooltip"    
    
function App() {    
  return (    
    <div>    
      <header>    
        <img src={logo} className="App-logo" alt="logo" />                  
      </header>          
      <div>    
        <Tooltip>Hello World !</Tooltip>    
      </div>    
    </div>    
  );    
}    
    
export default App;  

The output will be displayed as below.

So, in this way, we can also customize a component for extra functionalities like creating models, Tooltip, etc.

Error Boundary

In React, there is a concept for Error Boundary that prevents the errors being thrown to the user. So, if any error occurs, this will display a user-friendly view. This Error Boundary component is a component that catches JavaScript errors from their child component trees, log those errors, and display a fallback UI in place of the component tree crashed errors thrown by the application. Error Boundaries catch errors during rendering, in lifecycle methods, and in constructor inside the whole trees. Error Boundaries are created as a class boundary when any one or both of these methods are defined -  static getDerievedStateFromError() or componentDidCatch().

The above 2 error methods are used to catch error UI and log error information respectively.

static getDerievedStateFromError()

This method is invoked after an error is thrown by the child component. It gets the error thrown by the child component as a parameter and it should return the value to update state.

The below code is a basic syntax to use Error Boundary.

import React,{Component} from 'react';    
    
class ErrorBoundary extends Component{    
    constructor(props) {    
        super(props)    
        
        this.state = {    
            hasError : false    
        }    
    }    
    
    static getDerivedStateFromError(error){    
        return {hasError:true};    
    }    
    
    render(){    
        if(this.state.hasError){    
            return <h2>Error Occurred</h2>                
        }    
        return this.props.children;    
    }    
}    
    
export default ErrorBoundary    

As the getDerievedFromState() method is called during the render phase just to set the state in React, so it does not involve any side effects. So, for that, we need to use the componentDidCatch() method.

componentDidCatch()

This method is used to log error information thrown during the getDerievedFromState() method.

Syntax - componentDidCatch(error,info)

import React,{Component} from 'react';    
    
class ErrorBoundary extends Component{    
    constructor(props) {    
        super(props)    
        
        this.state = {    
            hasError : false    
        }    
    }    
    
    static getDerivedStateFromError(error){    
        return {hasError:true};    
    }    
    
    componentDidCatch(error,info){    
      // Any reporting Service of custom code to set state    
    }    
        
    render(){    
        if(this.state.hasError){    
            return <h2>Error Occurred</h2>                
        }    
        return this.props.children;    
    }    
}    
    
export default ErrorBoundary   

The lifecycle is invoked when an error is thrown from a child component. It takes 2 parameters.

error - The error that was thrown

Info - An object with ComponentStack key containing information about which component threw the error.

componentDidCatch() is called during commit phase, so side effects are permitted and used for logging errors.

Some important point to keep in mind while using Error Boundary,

1. Error boundaries do not catch error in below cases,
2. Thrown in error boundary itself.
3. Event handlers
4. for Async Code
5. Server Side rendering
6. Only class components can be error boundaries
7. Error boundaries work like javascript catch {} block, but just for a component.

Let’s see a demo for Error Boundary.

ErrorBoundary.js

import React,{Component} from 'react';    
    
class ErrorBoundary extends Component{    
    constructor(props) {    
        super(props)    
        
        this.state = {    
            hasError : false    
        }    
    }      
    static getDerivedStateFromError(error){    
        return {hasError:true};    
    }      
    componentDidCatch(error,info){    
        this.setState({    
            hasError:true    
        })    
    }          
    render(){    
        if(this.state.hasError){    
            return <h2>Error Occured</h2>                
        }    
        return this.props.children;    
    }    
}      
export default ErrorBoundary    

Just change a method name to generate error in Tooltip.js

import React, { Component } from 'react'      
class Tooltip extends Component {    
  constructor(props) {    
    super(props)    
    this.state = { hover: false }    
  }        
  handleMouseIn() {    
    this.setState({ hover: true })    
  }        
  handleMouseOut() {    
    this.setState({ hover: false })    
  }        
  render() {    
    const tooltipStyle = {    
      display: this.state.hover ? 'block' : 'none'    
    }    
    return (      
      <div>    
        <div onMouseOver={this.handleMouseIn.bind(this)} onMouseOut={this.handleMouseOut1.bind(this)}>on hover here we will show the tooltip</div>    
        <div>    
          <div style={tooltipStyle}>this is the tooltip!!</div>    
        </div>    
      </div>    
    );    
  }    
}      
export default Tooltip    

Now in App.js file

import React from 'react';    
import logo from './logo.svg';    
import './App.css';    
import Tooltip from "./components/Tooltip"    
import ErrorBoundary from "./components/ErrorBoundary"    
    
function App() {    
  return (    
    <ErrorBoundary>    
    <div>    
      <header>    
        <img src={logo} className="App-logo" alt="logo" />                  
      </header>          
      <div>    
        <Tooltip>Hello World !</Tooltip>    
      </div>    
    </div>    
    </ErrorBoundary>    
  );    
}    
    
export default App;    

The output will be displayed as below,

Here you will note a change. After displaying the above screen just after a few seconds error page is displayed again as below,

This is because in development phase Error Boundaries do not override error overlay. Which may not happen in the production phase. To resolve this issue you can add below code in your CSS file.

iframe {    
  display: none;    
}  

Then, the text or image you want to display using the error boundary will remain on browser’s screen.

Summary

In this article, we have learned about Portals and Error Boundary in React.

Thank you for reading !

#react #portals #error #tutorial

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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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Understand to Use Portal and Error Boundary in React

In this article, we will learn about React Portal and Error Boundary and how it can be used in React.

Portal

A React Portal is a way of binding an element outside of its component hierarchy, in a separate component. The name Portal represents that an element can be set anywhere in the DOM tree that’s outside of the normal React components tree. The concept of Portal is added after version 16.0 in React.

React provides an API to create portal named ReactDOM.createPortal() that accepts 2 parameters, the first parameter is an element which needs to be rendered and the second element is the DOM element in which it needs to be rendered. Portals are mostly used for implementing, Tooltip, Modals, Global message notifications, hovercards, chat widgets, and Floating menus. For Portal, we can return strings, numbers, components, React portals or an array of children.

Event Bubbling through React Portals

As React portal can be anywhere outside of DOM tree but it will act like a React child in all other ways, despite the fact that a child is a portal, it will still exist in the React tree regardless of its position in the DOM tree. So, if we want to trigger any event from the Portal, it will propagate to ancestors in the containing tree, even if those elements are not ancestors of the DOM tree.

Let’s look at the demo that will display tooltip using Portal.

import React, { Component } from 'react'    
    
class Tooltip extends Component {    
  constructor(props) {    
    super(props)    
    this.state = { hover: false }    
  }    
      
  handleMouseIn() {    
    this.setState({ hover: true })    
  }    
      
  handleMouseOut() {    
    this.setState({ hover: false })    
  }    
      
  render() {    
    const tooltipStyle = {    
      display: this.state.hover ? 'block' : 'none'    
    }    
        
    return (    
    
      <div>    
        <div onMouseOver={this.handleMouseIn.bind(this)} onMouseOut={this.handleMouseOut.bind(this)}>on hover here we will show the tooltip</div>    
        <div>    
          <div style={tooltipStyle}>this is the tooltip!!</div>    
        </div>    
      </div>    
    );    
  }    
}    
    
export default Tooltip     

Now, use the Tooltip component in the App component.

import React from 'react';    
import logo from './logo.svg';    
import './App.css';    
import Tooltip from "./components/Tooltip"    
    
function App() {    
  return (    
    <div>    
      <header>    
        <img src={logo} className="App-logo" alt="logo" />                  
      </header>          
      <div>    
        <Tooltip>Hello World !</Tooltip>    
      </div>    
    </div>    
  );    
}    
    
export default App;  

The output will be displayed as below.

So, in this way, we can also customize a component for extra functionalities like creating models, Tooltip, etc.

Error Boundary

In React, there is a concept for Error Boundary that prevents the errors being thrown to the user. So, if any error occurs, this will display a user-friendly view. This Error Boundary component is a component that catches JavaScript errors from their child component trees, log those errors, and display a fallback UI in place of the component tree crashed errors thrown by the application. Error Boundaries catch errors during rendering, in lifecycle methods, and in constructor inside the whole trees. Error Boundaries are created as a class boundary when any one or both of these methods are defined -  static getDerievedStateFromError() or componentDidCatch().

The above 2 error methods are used to catch error UI and log error information respectively.

static getDerievedStateFromError()

This method is invoked after an error is thrown by the child component. It gets the error thrown by the child component as a parameter and it should return the value to update state.

The below code is a basic syntax to use Error Boundary.

import React,{Component} from 'react';    
    
class ErrorBoundary extends Component{    
    constructor(props) {    
        super(props)    
        
        this.state = {    
            hasError : false    
        }    
    }    
    
    static getDerivedStateFromError(error){    
        return {hasError:true};    
    }    
    
    render(){    
        if(this.state.hasError){    
            return <h2>Error Occurred</h2>                
        }    
        return this.props.children;    
    }    
}    
    
export default ErrorBoundary    

As the getDerievedFromState() method is called during the render phase just to set the state in React, so it does not involve any side effects. So, for that, we need to use the componentDidCatch() method.

componentDidCatch()

This method is used to log error information thrown during the getDerievedFromState() method.

Syntax - componentDidCatch(error,info)

import React,{Component} from 'react';    
    
class ErrorBoundary extends Component{    
    constructor(props) {    
        super(props)    
        
        this.state = {    
            hasError : false    
        }    
    }    
    
    static getDerivedStateFromError(error){    
        return {hasError:true};    
    }    
    
    componentDidCatch(error,info){    
      // Any reporting Service of custom code to set state    
    }    
        
    render(){    
        if(this.state.hasError){    
            return <h2>Error Occurred</h2>                
        }    
        return this.props.children;    
    }    
}    
    
export default ErrorBoundary   

The lifecycle is invoked when an error is thrown from a child component. It takes 2 parameters.

error - The error that was thrown

Info - An object with ComponentStack key containing information about which component threw the error.

componentDidCatch() is called during commit phase, so side effects are permitted and used for logging errors.

Some important point to keep in mind while using Error Boundary,

1. Error boundaries do not catch error in below cases,
2. Thrown in error boundary itself.
3. Event handlers
4. for Async Code
5. Server Side rendering
6. Only class components can be error boundaries
7. Error boundaries work like javascript catch {} block, but just for a component.

Let’s see a demo for Error Boundary.

ErrorBoundary.js

import React,{Component} from 'react';    
    
class ErrorBoundary extends Component{    
    constructor(props) {    
        super(props)    
        
        this.state = {    
            hasError : false    
        }    
    }      
    static getDerivedStateFromError(error){    
        return {hasError:true};    
    }      
    componentDidCatch(error,info){    
        this.setState({    
            hasError:true    
        })    
    }          
    render(){    
        if(this.state.hasError){    
            return <h2>Error Occured</h2>                
        }    
        return this.props.children;    
    }    
}      
export default ErrorBoundary    

Just change a method name to generate error in Tooltip.js

import React, { Component } from 'react'      
class Tooltip extends Component {    
  constructor(props) {    
    super(props)    
    this.state = { hover: false }    
  }        
  handleMouseIn() {    
    this.setState({ hover: true })    
  }        
  handleMouseOut() {    
    this.setState({ hover: false })    
  }        
  render() {    
    const tooltipStyle = {    
      display: this.state.hover ? 'block' : 'none'    
    }    
    return (      
      <div>    
        <div onMouseOver={this.handleMouseIn.bind(this)} onMouseOut={this.handleMouseOut1.bind(this)}>on hover here we will show the tooltip</div>    
        <div>    
          <div style={tooltipStyle}>this is the tooltip!!</div>    
        </div>    
      </div>    
    );    
  }    
}      
export default Tooltip    

Now in App.js file

import React from 'react';    
import logo from './logo.svg';    
import './App.css';    
import Tooltip from "./components/Tooltip"    
import ErrorBoundary from "./components/ErrorBoundary"    
    
function App() {    
  return (    
    <ErrorBoundary>    
    <div>    
      <header>    
        <img src={logo} className="App-logo" alt="logo" />                  
      </header>          
      <div>    
        <Tooltip>Hello World !</Tooltip>    
      </div>    
    </div>    
    </ErrorBoundary>    
  );    
}    
    
export default App;    

The output will be displayed as below,

Here you will note a change. After displaying the above screen just after a few seconds error page is displayed again as below,

This is because in development phase Error Boundaries do not override error overlay. Which may not happen in the production phase. To resolve this issue you can add below code in your CSS file.

iframe {    
  display: none;    
}  

Then, the text or image you want to display using the error boundary will remain on browser’s screen.

Summary

In this article, we have learned about Portals and Error Boundary in React.

Thank you for reading !

#react #portals #error #tutorial

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

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

React 18: Things You Need To Know About React JS Latest Version

The most awaited version of React 18 is finally out now. Its team has finally revealed the alpha version of React 18 and its plan, though the official launch is still pending. This time the team has tried something and released the plan first to know their user feedback because the last version of React 17 was not that much appreciated among developers.

According to Front-end Frameworks Survey, React JS has ranked top in the list of most loved frameworks. Thus, the developer communities expect a bit higher from the framework, so they are less appreciative of the previous launch.
So, this time React 18 will be a blast. For beginners, the team is working on a new approach. They have called a panel of experts, library authors, educators, and developers to take part in a working group. Initially, it will be a small group.

I am not a part of this release but following the team on their GitHub discussion group. After gathering the information from there, I can say that they have planned much better this time.

React 17 was not able to meet the developer's community. The focus was all primarily centered on making it easier to upgrade React itself. React 18 release will be the opposite. It has a lot of features for react developers.

Read more here: React 18: Things You Need To Know About React JS Latest Version

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