6 Pro Tips from React Developers

6 Pro Tips from React Developers

☞ 

#Reactjs #Developers

  • If you’re new to React, you could benefit from learning from the success—and failures—of React developers who’ve learned valuable lessons about the framework.
  • If you don’t need internal state or lifecycle methods on your component, use a functional component instead.
  • A functional component is a pure JavaScript function that accept as its argument and returns a React element.
  • But if you are using an ES6 class, you’ll need to bind manually since React doesn’t autobind the functions inside that component.
  • With React Developer Tools, available as a Google Chrome and Firefox extension, as well as a standalone app for other environments, you can quickly view your component hierarchy, inspect and edit a component’s props and state, and invoke methods on a component within the DevTools.

If you’re new to React, you could benefit from learning from the success—and failures—of React developers who’ve learned valuable lessons about the framework.
Continue reading “6 Pro Tips from React Developers”

6 Pro Tips from React Developers

6 Pro Tips from React Developers

☞ 

#Reactjs #Developers

  • If you’re new to React, you could benefit from learning from the success—and failures—of React developers who’ve learned valuable lessons about the framework.
  • If you don’t need internal state or lifecycle methods on your component, use a functional component instead.
  • A functional component is a pure JavaScript function that accept as its argument and returns a React element.
  • But if you are using an ES6 class, you’ll need to bind manually since React doesn’t autobind the functions inside that component.
  • With React Developer Tools, available as a Google Chrome and Firefox extension, as well as a standalone app for other environments, you can quickly view your component hierarchy, inspect and edit a component’s props and state, and invoke methods on a component within the DevTools.

If you’re new to React, you could benefit from learning from the success—and failures—of React developers who’ve learned valuable lessons about the framework.
Continue reading “6 Pro Tips from React Developers”

React State From the Ground Up

#ReactJS State From the Ground Up #JavaScript

  • State, in React, is a plain JavaScript object that allows you keep track of a component’s data.
  • The initial state of the App component has been set to a state object which contains the key username, and its value using .
  • Initializing a component state can get as complex as what you can see here: – – An initialized state can be accessed in the method, as I did above.
  • Your component should look like this; – – A state can be passed as props from a parent to the child component.
  • This method will be used to update the state of the component.

As you begin to learn React, you will be faced with understanding what state is. State is hugely important in React, and perhaps a big reason you’ve looked into using React in the first place. Let’s take a stab at understanding what state is and how it works. What is State? State, in React, is a plain JavaScript
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Step by step guide for writing awesome React components

  • Now imagine the most verbose way to write it.class SlothImage extends React.Component { render() { return img src=’sloth.gif’ alt=’Pretty face’ }}export default SlothImageThis code is completely correct and performant but can it be shorter?
  • This component has no use of lifecycle methods.const SlothImage = props = { return img src=’sloth.gif’ alt=’Pretty face’}export default SlothImageTwo lines have been spared by converting the class component to the functional component.
  • /*The props should now be built like this:{ src: ‘sloth.gif’, alt: ‘Pretty face’,}*/export default props = img {…props}The dots are called a spread operator (❧).
  • My personal taste for writing more complex components is as follows:export default ({ separateNext: underline, rightComponent, onRightComponentClick, …rest: imgProps}) = { return ( Row underline SlothImage {…imgProps} / /Row )}If I could pick one rule in writing React components it would be exceeding the 80 characters mark (❧) in a…
  • The sign of overcomplication is the usage of “enum” like props or having too many props.TextInput required width=’col-6′ height=’xlarge’ bgColor=’#a4a4a4′ type=’primary’ suffix=’dollar’ 1337/TextInputEvery component should have a single responsibility (❧) and a reasonable amount of flexibility.

Going through the process of learning and using React and Redux I came to a following conclusion – they are not hard to grasp but are fairly difficult to master. Both are pretty minimal when it comes…
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Why do we need to understand the ReactJs life cycle methods?

Why do we need to understand the ReactJs life cycle methods?  #javascript

  • When you build an application in ReactJs you will have to split the UI into reusable components and think about each of them in isolation.When the user interacts with our application in ReactJs, for example, by hovering, pressing a key, clicking… These actions trigger many other events on the UI…
  • So, why is understanding lifecycle methods so important?Let’s imagine that you are building an application in ReactJs, for example, a video player app, like Vimeo, Twitch or Youtube .
  • Now, your user is using the player app on his/her laptop and decides to search for a fun video to watch, found the video, and then selected to watch it.Let’s suppose that the player app is consuming only resources like network data and the battery power.After some time watching videos…
  • When we build an application in ReactJs , we can predict different type of actions by the user, placing some hooks and triggers.These triggers and hooks are available by component lifecycle methods in Reactjs.
  • They will help us to create the most efficient piece of the software as possible.To place correctly the hook methods into the components we need to learn more about the four stages of ReactJs component.The ReactJs component goes through the Four following is a little diagram to demonstrate those phases.InitializationIn…

Components are the core of ReactJs. When you build an application in ReactJs you will have to split the UI into reusable components and think about each of them in isolation. When the user interacts…
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React Functional Components vs. Class Components – codeburst

  • Let’s have a look at an example:import React from “react”; import PropTypes from “prop-types”; const Person = ({firstName, lastName}) = ( div h1 {firstName} {lastName} /h1 /div ); Person.propTypes = { firstName: PropTypes.string.isRequired, lastName: PropTypes.string.isRequired } export default Person;As you can see, functional components are basically just the render function…
  • Instead, they focus solely on the UI and not on the behavior of the app.Also something worth mentioning: When you’re using functional components, you don’t have a this keyword to use.Now let’s have a look at class components, before we compare them and work out their different use cases.Class ComponentClass…
  • Have a look at the above example, rewritten as a ES6 class component.import React, { Component } from “react”; import PropTypes from “prop-types”; class Person extends Component { render() { return( div h1 {this.props.firstName} {this.props.lastName} /h1 /div ); } } Person.propTypes = { firstName: PropTypes.string.isRequired, lastName: PropTypes.string.isRequired } export default…
  • If needed, you can always rewrite them to class components later on, but most of the time you will just use them to arrange your UI and let the container components handle the state and logic.Container Components need their own state or make use of life cycle methods, therefore I…
  • You learned, that functional componentsdon’t have statedon’t have life cycle methodsdon’t have a thisare pure functions and therefore easy to testare easier to read and understandencourage you to keep in mind the best practicescan also be called presentational componentsIf you need anything that functional components don’t provide, use class components.Call…

Functional components are simpler and easier to test in comparison to class components. However, both of them have pros and cons and today you’ll learn the differences and when to use which type of…
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6 Pro Tips from React Developers — SitePoint

We've got 1 #reactjs tip from a pro devs for you. Watch  for all 6 tips.

  • Tip 1: Use functional components – Cam Jackson – If you don’t need internal state or lifecycle methods on your component, use a functional component instead.
  • A functional component is a pure JavaScript function that accept props as its argument and returns a React element.
  • Benefits of functional components: – – Less code – Easier to understand – The component is stateless, so you avoid accidentally storing state on a component you shouldn’t – The component is simpler to test – There’s no this binding – It’s easier to see where and when to extract…
  • Keep Tip 1 in mind and extract blocks of code into functional components whenever possible.
  • Tip 6: Use React Developer tools – Brian Gates – With React Developer Tools, available as a Google Chrome and Firefox extension, as well as a standalone app for other environments, you can quickly view your component hierarchy, inspect and edit a component’s props and state, and invoke methods on…

If you’re new to React, you could benefit from learning from React developers who’ve learned valuable lessons about the framework.
Continue reading “6 Pro Tips from React Developers — SitePoint”

Visualizing transit vehicle locations on a map in real-time

Visualizing transit vehicle locations on a map in real-time:  #ReactJS #JavaScript

  • I could just make requests to the restbus API at and display it on a map.
  • Most browsers block HTTPS websites from requesting insecure resources.Problem #2: I noticed that the public Restbus API went down when I made too many consecutive requests.
  • Running the chrome profiler showed me the following:The component update was taking 359s to update after each API request.
  • I also noticed that network requests take rather long.Let’s see if the restbus API returns any data we do not need.We’re only using a few fields out of this — id, routeId, secsSinceLastReport, lat, lon, and everything else can be ignored.
  • Future improvements to react will have performance optimizations to components declared this way by avoiding unnecessary checks, memory allocations and lifecycle methods.A hack to make functional components faster right now is to call them as functions, as opposed to JSX nodes.const Component = (props) = ( div{props}/div);// Using component in JSX = slowerdiv Component //div// Calling component as a regular function in curly braces = fasterdiv {Component()}/divAlthough I haven’t profiled it yet, there are several blog posts that report a big speedup.

In this blog post I’ll talk about how I built a visualization of Toronto Transit vehicle locations and some of the engineering challenges I ran into. A working demo can be found on my personal…
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Optimizing React Performance with Stateless Components — SitePoint

Optimizing React Performance with Stateless Components  #reactjs #javascript

  • First, the Super Basics
    import React, { Component } from ‘react’

    class User extends Component {
    render() {
    const { name, highlighted, userSelected } = this.props
    console.log(‘Hey User is being rendered for’, [name, highlighted])
    return div
    h3
    style={{fontStyle: highlighted ?

  • For example, something like this:
    import React, { Component } from ‘react’

    class Users extends Component {
    constructor(props) {
    super(props)
    this.state = {
    otherData: null,
    users: [{name: ‘John Doe’, highlighted: false}]
    }
    }

    async componentDidMount() {
    try {
    let response = await let data = await response.json()
    this.setState({otherData: data})
    } catch(err) {
    throw err
    }
    }

    toggleUserHighlight(user) {
    this.setState(prevState = {
    users: prevState.users.map(u = {
    if (u.name === user.name) {
    u.highlighted = !

  • import React, { PureComponent } from ‘react’

    class User extends PureComponent {

    render() {
    const { name, highlighted, userSelected } = this.props
    console.log(‘Hey User is being rendered for’, [name, highlighted])
    return div
    h3
    style={{fontStyle: highlighted ?

  • Our first attempt at re-writing it back to a functional component but with recompose.pure looks like this:
    import React from ‘react’
    import { pure } from ‘recompose’

    const User = pure(({ name, highlighted, userSelected }) = {
    console.log(‘Hey User is being rendered for’, [name, highlighted])
    return div
    h3
    style={{fontStyle: highlighted ?

  • ‘italic’ : ‘normal’}}
    onClick={event = {
    userSelected()
    }}{name}/h3
    /div
    })

    export default User

    As you might notice, if you run this, the User component still re-renders even though the props (the name and highlighted keys) don’t change.

Writing inefficient React components can cause them to rerender too often. Peter Bengtsson looks at ways of creating and optimizing stateless components.
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React v15.5.0

What do you think about React v15.5.0?



#ReactJS #React15 #JavaScript #Developer #WebDev

  • In 15.5, instead of accessing from the main object, install the package and import them from there:

    The codemod for this change performs this conversion automatically.

  • You may also consider using Flow to statically type check your JavaScript code, including React components.
  • Later, classes were added to the language as part of ES2015, so we added the ability to create React components using JavaScript classes.
  • Along with functional components, JavaScript classes are now the preferred way to create components in React.
  • The codemod for this change attempts to convert a component to a JavaScript class, with a fallback to if necessary.

It’s been exactly one year since the last breaking change to React. Our next major release, React 16, will include some exciting improvements, including a complete rewrite of React’s internals. We take stability seriously, and are committed to bringing those improvements to all of our users with minimal effort.
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