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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Top JavaScript Libraries & Tech to Learn in 2018 – JavaScript Scene – Medium

Top #JavaScript Libraries & Tech to Learn in 2018:  by @_ericelliott #ReactJS #Developers

  • There’s plenty of room for Vue.js to pick up a lot of Angular and jQuery users at a fast clip, but they will likely hit a brick wall when they have to start stealing users from React to continue the growth streak.
  • I predict strong Vue.js growth for another year or two, followed by a much harder battle with React in the top spot and Vue.js relegated to second fiddle unless something big changes to upset the balance.
  • Why so Much Interest in React?Browsing through the React job listings, I noticed an interesting trend — a lot of them were for things that we don’t think of as front-end web work: – React Native (for perspective, there are more of these openings than the total number of Vue.js openings)React for IoTReact…
  • Which Topics Should You Study?Like last year, you can’t go wrong focusing on the essentials, but you should place more emphasis on functional programming for React apps.
  • With that in mind, here are some topics you should study: – Basic ES6 syntaxClass syntax and its many pitfalls — It’s OK to use class for React components, but avoid extending from your own classes, avoid instanceof, and avoid forcing users of your classes to use the new keyword.Functional programming software…

Last year, I wrote an article rounding up the top tech to learn in 2017. This year there are some surprises. First, software ate the world, the web ate software, and JavaScript ate the web. In 2018…
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A simple React.js on MacOS Setup

  • The node package manager is used to install libraries/frameworks (node packages), such as React, on the command line to your project.
  • That’s why my recommendation would be Visual Studio Code to start developing React applications on MacOS.
  • The installation on a MacOS machine is simple: Navigate to the official Visual Studio Code website and download the recent version of VS Code.
  • That’s your integrated command line in Visual Studio Code to install node packages with NPM or to start/test your project.
  • On the command line (in Visual Studio Code), type the following command to install create-react-app: – – This package allows you to bootstrap React applications with zero-configuration.

A concise step by step guide on how to setup React.js on MacOS. In a few steps, you will install Visual Studio Code, Node.js, NPM, Git, Prettier and create-react-app for building React applications with Mac OS …
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Release v4.0.0-rc.2 · invertase/react-native-firebase · GitHub

  • Plus, we’ve got Firebase Invites, Multi-Database url support and an overhaul of Dynamic Links – – We have made the conscious decision to separate this functionality into two distinct areas: – – You can read some more here: our previous implementation, we had a single listener which was triggered for…
  • To simplify things, we’ve broken out a number of different listeners to provide greater control and customisation: – – Read more here: and our previous implementation, we relied on the flag existing within the notification content to force the library to automatically show the notification if the app was running…
  • Whilst this (kind of) worked, it meant it was down to the notification sender to control the display of the notification, not the app itself.
  • When the app is in the background, the OS will automatically handle the notification display when a remote or local notification is received.
  • Check out the createDynamicLink docs and Dynamic Link reference docs – – Database now supports using multiple database instances via database urls e.g.: – – As you can imagine, for Messaging and Notifications this is a completely breaking change, so you’ll want to follow the installation instructions available here: -…

GitHub is where people build software. More than 27 million people use GitHub to discover, fork, and contribute to over 80 million projects.
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Easily Build Forms in React Native – React Native Development – Medium

Easily Build Forms in React Native -

  • A few things you might have to take care of… – Creating the necessary components (text inputs, select inputs, checkboxes, switches, etc)Writing/finding validation logicUpdating your components to display any errors (I always forget to do this)Updating your UI whenever you change fieldsNone of these things are difficult, but they can…
  • What We’re BuildingWe’ll be building a sign up form that has the following fields – Email (required)Username (optional)Password (required)Agree to terms (required)Defining the Form ModelThe first thing we need to do is define a model for our form — this is what will be passed to the form component and used to render the…
  • First we need to get the Form component (line 6) then we need to render the form and pass our model to it as the type (line 19).
  • Then pass those options to the Form component – Let’s do the same thing to add some error the Form DesignThe final thing I want to do is modify the design of this form slightly.
  • You can do quite a few things but I’m just going to be changing the label color on this one form.

If you’re building a React Native app it’s almost a guarantee that you’ll have to build at least one form. The reality is you’ll probably build quite a few (sign in, sign up, edit profile, etc.)…
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Choosing Between React and Vue For WordPress Development

Choosing Between #ReactJS and #VueJS For WordPress Development -

  • In React, component state is mutated using the function setState(), while in Vue, you just change the variable value directly or you use v-model directive in an HTML template and it’s all magical.
  • Any mildly complex Vue or React app needs state management — using Redux, V\uex or similar — for app state and that involves state update function.
  • When creating React or Vue components this way, you have to write your own change handlers to modify state.
  • Vue’s data model is inspired by React and other frameworks based on observables.
  • In the React world create-react-app is a CLI tool, like Vue CLI for scaffolding apps.

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Optional Chaining Operator in JavaScript – Bene Studio

  • var user = { name: ‘Joe’ } – var zip = // ⚡⚡⚡Uncaught TypeError: Cannot read property ‘zip’ of undefinedIn this example we expect to exist but for some reason the address is missing from the user object.
  • Workaround #1: Logic Expressionsvar user = { name: ‘Joe’ } – var zip = user – user.address – user.address.zipNoisy and verbose.
  • Workaround #2: Ternary Operatorsvar user = { name: ‘Joe’ } – var zip = – user === undefined – ?
  • Workaround #3: Try-Catchvar user = { name: ‘Joe’ } – var ziptry { – zip = – } catch (error) { – zip = null – }Breaks control and has own scopes.
  • bin/babel index.jsThe Transpiled CodeTranspiled version of the index.js above: – var _user$address;var user = { – name: ‘Joe’ – };var zip = – user == null – ?

All of us usually confronts the situation where an expected member of a property chain is undefined or null. In this example we expect to exist but for some reason the address is…
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nohoist in Workspaces

  • First, let’s take a quick tour on how hoist work in standalone projects: – – To reduce redundancy, most package managers employ some kind of hoisting scheme to extract and flatten all dependent modules, as much as possible, into a centralized location.
  • In such project, modules could be scattered in multiple locations: – – yarn workspaces can share modules across child projects/packages by hoisting them up to their parent project’s node_modules: .
  • Consequently, workspaces developers often witness “module not found” related errors when building from the child project: – – For this monorepo project to reliably find any module from anywhere, it needs to traverse each nodemodules tree: *“monorepo/nodemodules”* and .
  • There are indeed many ways library owners can address these issues, such as multi-root, custom module map, clever traversing scheme, among others… However, – – It is frustrating when a solution worked for a standalone project only fell short in the monorepo environment.
  • Module path is a virtual path of the dependency tree, not an actual file path, so no need to specify “node_modules” or “packages” in the nohoist pattern.

As wonderful as yarn workspaces are, the rest of the community hasn’t yet fully caught up with the monorepo hoisting scheme. The introducing of the nohoist i…
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New context API by acdlite · Pull Request #11818 · facebook/react · GitHub

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react – A declarative, efficient, and flexible JavaScript library for building user interfaces.
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