React Components Explained – codeburst

  • Something like thisimport React from ‘react’;class MyComponent extends React.Component { render () { return div This is a component /div }}class MyOtherComponent extends React.Component { render () { return ( div MyComponent / /div ) }}This way you are able to compose more complex and useful user interface for your…
  • Component’s render method return JSX which then use to create real HTML output which will be rendered in the browser.The interesting Thing about render method is that it runs every time when your component State or Props updates.
  • Let me show you a exampleimport React from ‘react’;class MyComponent extends React.Component { constructor(props) { super(props); this.state = { name: “Manoj” }; } render () { return div My name is {this.state.name} /div }}// if we render this component the output will beMy name is ManojIgnore the super(props) (out of…
  • Let’s see an example.class MyComponent extends React.Component { constructor(props) { super(props); this.state = { name: “Manoj” }; this.changeName = this.changeName.bind(this); } changeName () { this.setState({ name: “Your Name” }); } render () { return div onClick={this.changeName} My name is {this.state.name} /div }}In the above code we are telling our React…
  • You can run this code on jsFiddle here.PropsVisualise props as options that can be passed to a component to customize its functionality.For example, I have a heading component which renders a heading with subtitle.class MyHeading extends React.Component { render () { return div h1This is a heading/h1 pSubtitle/p /div }}If…

The simplest library I ever used in my life is React. As you know React is based upon component design. Everything in React is a component which makes it easy to reuse components frequently. You can…
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Math: the React.js Way – Hacker Noon

Math: the React.js Way

☞ 

#reactjs #javascript

  • Math: the React.js WayHave you found yourself doing intense math problems using weird symbols like +, −, á, and×?
  • Thanks to react-real-math you can now harness the power of the React.js Virtual DOM to make your Math blazing🔥 fast!react-real-math provides an incredibly easy to understand API out of the gate, for free.
  • Let’s take a look at an example of react-real-math in action.
  • Consider this old-school almost obfuscated math problem:1+1×2=?
  • If you would like to contribute to react-real-math please check out the project’s

Have you found yourself doing intense math problems using weird symbols like +, −, ÷, and×? Do you enjoy the speed and developer experience of React.js? Thanks to react-real-math you can now harness…
Continue reading “Math: the React.js Way – Hacker Noon”

Using JSX and React #React #reactjs #javascript #Framework #programming

Using JSX and React  #React #reactjs #javascript #Framework #programming

  • Form creation is easy with JSX and sub-components, for example: – – To make this work, you must create the sub-components as attributes of the main component: – – To use some JavaScript to create a result for use in an attribute value, React just needs you to wrap it…
  • _disconnectFrom(userId); self.emit(events.DISCONNECT, userId); console.log(‘User disconnected’, userId); }); }); console.log(‘Connecting with username’, username); this.peer = new Peer(username, { host: location.hostname, port: 9000, path: ‘/chat’ }); this.peer.on(‘open’, function (userId) { self.setUsername(userId); }); this.peer.on(‘connection’, function (conn) { self.
  • First we use to establish signalling of a new user connected via the as so: – – js ChatServer.prototype.connect = function (username) { var self = this; this.setUsername(username); this.socket = io(); this.socket.on(‘connect’, function () { self.socket.on(events.CONNECT, function (userId) { if (userId === self.getUsername()) { return; } self.
  • _connectTo(userId); self.emit(events.CONNECT, userId); console.log(‘User connected’, userId); }); – – Then, to connect to the PeerServer, we use the following: – – We then listen for events via the method: – – We also have our JSX inside components in the directory.
  • Now it’s as simple as pushing your code to heroku: – – Once the push is finished, you will be able to start your web service with the following: – – Now just visit the URL provided, or as a shortcut use the command as so: – – You’ve learned…

What You’ll Be CreatingJSX is similar to a mix of XML and HTML. You use JSX within React code to easily create components for your apps. JSX transforms into JavaScript when React compiles the…
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The most unknown redux performance trick – Julien De Luca – Medium

  • The most unknown redux performance trickRegarding optimizing redux, there are some well known techniques: memoizing, using reselect for example.But there is one that remains unknown to many, although it’s simple and very efficient: The connect’s areStatesEqual option.When state changes, all connect functions will be called, props mapped from state and…
  • Imagine something like this :Considering action addTodo adds a todo item in the todo reducer, when this action will be called, both connect will then be called and mapStateToProps computed.Using areStatesEqual option, you can tell when not to bother to call mapStateToProps at all.The docs say :[areStatesEqual] (Function): When pure, compares incoming…
  • This function is passed 2 arguments: the previous state, and the next state.
  • You return a boolean telling whether the two states have changed, regarding the state slice you’re interested in, and if the function returns true, mapStateToProps will not even be called.Let’s update our example to use this function :Now, when state.users.all changes, the TodoContainer’s areStatesEqual option will be called, it will return…
  • It makes much more sense when using more complex mapStateToProps.Memoization remains useful when using props in mapStateToProps and methods that return new objects or arrays.Perfs gain can be really impressive only using this simple trick.Enjoy !

Regarding optimizing redux, there are some well known techniques: memoizing, using reselect for example. But there is one that remains unknown to many, although it’s simple and very efficient: The…
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React Js Tutorial – React Component Lifecycle, State, Props #reactjs #javascript

  • Do you know what is meant by component lifecycle, state, props in React Js?
  • In this tutorial, you will learn about, – – The render method is the only required spec for the components.
  • If the component doesn’t need to render after state or props change then we can set it to false.
  • Every component has a state object and props object.
  • Let’s see the example of state and props below.

Learn about react lifecycle, state, props.Also, know the difference between state and props in this tutorial.Find out the complete react js tutorial here.
Continue reading “React Js Tutorial – React Component Lifecycle, State, Props #reactjs #javascript”

Math: the React.js Way – Hacker Noon

Math: the React.js Way

☞ 

#reactjs #javascript

  • Math: the React.js WayHave you found yourself doing intense math problems using weird symbols like +, −, á, and×?
  • Thanks to react-real-math you can now harness the power of the React.js Virtual DOM to make your Math blazing🔥 fast!react-real-math provides an incredibly easy to understand API out of the gate, for free.
  • Let’s take a look at an example of react-real-math in action.
  • Consider this old-school almost obfuscated math problem:1+1×2=?
  • If you would like to contribute to react-real-math please check out the project’s

Have you found yourself doing intense math problems using weird symbols like +, −, ÷, and×? Do you enjoy the speed and developer experience of React.js? Thanks to react-real-math you can now harness…
Continue reading “Math: the React.js Way – Hacker Noon”

Improving the usability of your modules – kentcdodds

Improving the usability of your modules  #reactjs

  • All you have to do is use it:import getContentForFile from ‘react-i18n’const i18n = App() { return ( div h1{i18n(‘header.title’)}/h1 /div )}So that’s how it works (again, I’m sure some of you are thinking of other libs that could do this better, but please spare me the “well actually.” I’m aware…
  • const content = JSON.parse( … more stuffexport {getContentForFile as default, init}This presents a few challenges for users of the module.
  • Turns out that react-i18n actually exposed another module react-i18n/bootstrap to customize this behavior which is great, but that doesn’t resolve the problem of stuff happening if someone were to import react-i18n first.So what I did was a wrapped all side-effects in a function I exported called init(which was similar to…
  • But it’s ok now because that’s clear const messages = JSON.parse( ) // … other other stuff}// … more stuffexport {getContentForFile as default, init}So this means that anyone using the module now must call the init function, but they’re doing that on their own terms and whenever they want it…
  • However, we’re in the process of “inner sourcing” this module (and perhaps open sourcing it eventually), so folks are going to use it who use different tools and have different use cases.So, if it’s not too much work and doesn’t add too much complexity, then try to make the solution…

NOTE: This is a cross-post from my newsletter. I publish each email two weeks after it’s sent. Subscribe to get more content like this earlier right in your inbox! 💌 This last week I worked on my…
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