How to handle state in React. – React Ecosystem – Medium

How to handle state in React. The missing FAQ.


#Reactjs #javascript

  • Each one corresponding to the way you create the component: – // Using React.createClass – var Counter = React.createClass({ – getInitialState: function() { – return {counter: 0}; – }, – …});// Using ES6 classes – class Counter extends React.Component { – constructor(props) { – super(props); – this.state = {counter: 0};…
  • Let’s exemplify: – // Don’t duplicate data from props in state – // Antipatternclass Component extends React.Component { – constructor(props) { – super(props); – this.state = {message: props.message}; – } – – render() { – return div{this.state.message}/div; – } – }The problem with the above example is it will only…
  • You can do better just by avoiding this situation: – // Better exampleclass Component extends React.Component { – render() { – return div{this.props.message}/div; – } – }The same applies when you hold state based on props calculation: – // Don’t hold state based on props calculation – // Antipatternclass Component…
  • // Antipatternclass Component extends React.Component { – constructor(props) { – super(props); – this.state = {count: 0}; – } – – render() { – return div{this.state.count}/div; – } – – componentDidMount() { – const interval = setInterval(() = ( – this.setState({count: this.state.count + 1}) – ), 1000); this.setState({interval}); – } componentWillUnmount()…
  • Let’s experiment a little bit to see what happens: – class Component extends React.Component { – constructor(props) { – super(props); – this.state = {count: 0}; – this.onClick = this.onClick.bind(this); – } – – render() { – return div } – – onClick() { – this.setState({count: this.state.count + 1}); – }…

Recently there has been a lot of debate about how to manage the state in React. Some claim that setState() doesn’t work as you might expect. That you have to externalize the state using a Flux-like…
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Redux vs MobX: Which Is Best for Your Project?

Redux vs MobX: Which Is Best for Your Project?


#Reactjs #javascript

  • I’ve migrated this CRUD Redux project to MobX to use as an example in this article.
  • The code for the projects mentioned in this article can be found on GitHub: – – If you enjoy this post, you might also like to sign up for SitePoint Premium and watch our course on working with forms using React and Redux.
  • If you prefer writing object-oriented code, you’ll be pleased to know you can use OOP to implement state management logic with MobX.
  • Believe it or not, the logic defined in both versions do the same tasks, which are: – – In Redux, we’ve used 33 lines of code.
  • A major benefit of the MobX version is that you can reuse the base code in almost all the domain store classes with little or no modification.

For a lot of JavaScript developers, the biggest complaint with Redux is the amount of boilerplate code needed to implement features
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Celebrating a Joyful JavaScript Certification

  • Although I had taken few online courses on JavaScript, I always lacked confidence in my JavaScript skills, because I had learned the language from a variety of sources and felt that there were several gaps in my JavaScript understanding.
  • Furthermore, as far as my freelance programming experience goes, I can tell that JavaScript developers are always busy, since they get the most freelance jobs (when classified by programming languages for web development).
  • However, since I already had a decent experience with JavaScript, I didn’t want to go through another course to earn a certificate (furthermore, I already had such certificates).
  • So I soon loaded up the JavaScript certification exam page for details about cost and exam process.
  • The first part of the exam was a theoretical test containing 20 single and multiple choice questions, each of which had a time limit of 1.5 minutes.

This post tells the story of my JavaScript certification preparation and success.
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Understanding React — Component life-cycle – Bartosz Szczeciński – Medium

Understanding React — Component life-cycle


#reactjs #JavaScript

  • In all other instances remember to use this.setState – DO – set initial stateif not using class properties syntax — prepare all class fields and bind functions that will be passed as callbacksDON’T – cause any side effects (AJAX calls etc.)componentWillMountThis is a somehow special case — componentWillMount does not differ much from constructor…
  • DO – update state via this.setStateperform last minute optimizationcause side-effects (AJAX calls etc.) in case of server-side-rendering onlyDON’T – cause any side effects (AJAX calls etc.) on client function will be called in each update life-cycle caused by changes to props (parent component re-rendering) and will be passed an object…
  • DO – use for increasing performance of poor performing ComponentsDON’T – cause any side effects (AJAX calls etc.)call nextState)If the shouldComponentUpdate function is not implemented, or it decided that the component should update in this render cycle, another life-cycle function will be called.
  • == this.props.myProp) { – // this.props.myProp has a different value – // we can perform any operations that would – // need the new value and/or cause side-effects – // like AJAX calls with the new value – this.props.myProp – } – }DO – cause side effects (AJAX calls etc.)DON’T…
  • DO – cause side effects (AJAX calls etc.)DON’T – call this.setState as it will result in a re-renderAn exception to the above rule is updating the state based on some DOM property which can be only computed once a component has re-rendered (e.g. position / dimensions of some DOM nodes)….

React provides developers with many methods or “hooks” that are called during the life-cycle of an component, which allows us to update the UI and application state. Knowing when to use which of them…
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Building AR & VR Applications using React Native

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These are my slides from the React Amsterdam talk on building Augmented Reality & Virtual Reality applications using React Native & Viro Media
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Building Mobile Applications with React Native. A brief introduction.

Building Mobile Applications with #reactnative. A brief introduction.

  • If you open your App.js you’ll encounter something along the lines of: – Components are the core of React Native, every visual element of your app is a component.
  • This styling cheat sheet is very handy when you’re getting started to check on what properties are available when styling components, but for a complete description the go to place is the online React Native documentation.
  • There are many basic elements that React Native provides as starting points and building blocks for our components: Views, ScrollViews, Text, TextInput, Touchable components that respond to touch input, Image, etc… As your UI starts growing and you have the need to add more and more Native components you’ll start…
  • Props and State – These are important concepts that will bring functionality, customisation and the ability to reuse components throughout your application.
  • We’ve created a new component that makes use of props and state to render a few text elements to the screen of our app’s.

The number of mobile devices is estimated to cross the 5 billion [1] mark between 2018 and 2019. This is pushing the mobile application development market forward, with the ever increasing demand for…
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Why ReactJS Is More in Demand

Why #ReactJS Is More in Demand

#WebDev #javascript  #WebApp

  • As stated already, the most compelling feature of React is that it reduces the complexities of user interface.
  • If the mechanism that we are trying to interface can comprehend Javascript, we can use React to build the user interface for it.
  • You describe the user interfaces in React languages and tell it what you want, it will take care to translate your description and prepare the actual interface.
  • You will illustrate user interfaces to React with simple components.
  • When state of a component changes, its User Interface will change automatically.

ReactJS is a JavaScript library for building user interfaces. According to Google Trends data last 5 years in increased popularity of ReactJS development and we explain why ReactJS is more in demand.
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