Found 217 Articles for Javascript Library

Some basics of react routingReact-router is the main library and react-router-dom and react-router-native are the environment specific libraries. React-router-dom is used in browser based web applications generally. react-router-native is used in mobile based applications which can be developed using react-native.To install it use command npm install –save react-router-domThere are two types of router in case of web applications.BrowserRouterHashRouterThe difference between the two router types are visible in the way they formulate the URLs.e.g. http://hello.com/about => BrowserRoutere.g. http://hello.com/#/about => HashRouter (uses hash in it)BrowserRouter is more popular and it uses html5 history API to keep track of locations.HashRouter supports the legacy ... Read More

There are multiple ways to add bootstrap in react project.Using bootstrap CDNInstalling bootstrap dependencyUsing react bootstrap packagesUsing bootstrap CDNThis is the simplest way to add bootstrap. Like other CDN, we can add bootstrap CDN in index.html of the react project.Below is one of the react CDN urlIf we need the JavaScript components of bootstrap then we should add the jquery, popper.js in the index.htmlWith this the complete index.html will look like − React App hello             Adding bootstrap dependencynpm install bootstrap ... Read More

We bundle the files in React application using tool such as webpack. Bundling in the end merges the files in the sequence of their imports and creates a single file.The problem with this approach is that the bundle file gets larger with the increase in files. User may not be sung all the feature components but still bundle is loading them, this could affect the loading of application.To avoid this, code splitting is used in React.ExampleExample of bundling −// app.js import { total } from './math.js'; console.log(total(10, 20)); // 42 // math.js export function total(a, b) {    return a ... Read More

The aria-* attributes on html elements are also supported in React.js as well. The other attributes are generally written in camel-case but these aria-* are written in hyphen-cased.Sometimes we break the semantics of the html if we use parent div in React.jsExamplerender(){    return(                Test          ); }Div can cause semantics issue if working with table, list etc. To avoid this we can use React provided fragment as shown below −import React, { Fragment } from ‘react’; function MessageList({ message }) {    return (       ... Read More

React community has provided a direction on how to think in React way and build big , fast and scalable applications. React has reached multiple platforms and widely used a popular JavaScript UI interface library.Step 1 − Creating a simple mock serviceIf we need to make a server call and fetch data. We can create a mock service to start with and build a component to fetch and display data.Here we can include the processing of json in component and evaluating the expected result.Step 2 − Break the functionality into smaller componentsThe first Thing React suggest is to create the ... Read More

Composition and inheritance are the approaches to use multiple components together in React.js . This helps in code reuse. React recommend using composition instead of inheritance as much as possible and inheritance should be used in very specific cases only.Example to understand it −Let’s say we have a component to input username.Inheritanceclass UserNameForm extends React.Component {    render() {       return (                                       );    } } ReactDOM.render(    < UserNameForm />,    document.getElementById('root'));This sis simple to just input ... Read More

Often there will be a need to share state between different components. The common approach to share state between two components is to move the state to common parent of the two components. This approach is called as lifting state up in React.jsWith the shared state, changes in state reflect in relevant components simultaneously. This is a single source of truth for shared state components.ExampleWe have a App component containing PlayerContent and PlayerDetails component. PlayerContent shows the player name buttons. PlayerDetails shows the details of the in one line.The app component contains the state for both the component. The selected ... Read More

In controlled component form data is handled by React component by writing event handler for state updates. But in uncontrolled component, form data is handled by DOM itself.ref is used to receive the form value from DOM.Exampleclass UserNameForm extends React.Component {    constructor(props) {       super(props);       this.handleFormSubmit = this.handleFormSubmit.bind(this);       this.inputUserName = React.createRef();    }    handleFormSubmit(event) {       console.log('username: ' + this.inputUserName.current.value);       event.preventDefault();    }    render() {       return (                           ... Read More

Displaying a list on UI in ReactMap is JavaScript function which will return a new array for provided array as shown below −const originalNumbers = [ 2, 4, 6, 8, 10]; const squaredNumbers = originalNumbers.map( (number)=> number * number); console.log(“Squared Numbers==”squaredNumbers);Building a list in React is similar with the use of map function. Instead of just returning a square number , we will return a list element with value of square.const originalNumbers = [ 2, 4, 6, 8, 10]; const squaredNumbersList= originalNumbers.map((number) =>    {number*number} );Render on the screen with ui tag −ReactDOM.render(    { squaredNumbersList },    document.getElementById('root') );When ... Read More

Using conditional statements specific components can be rendered and removed . Conditional handling works similarly in JavaScript and React.jsExamplefunction DisplayUserMessage( props ){    const user = props.user.type;    if(type==’Player’){       return Player ;    }    If( type==’Admin’){       Return Admin ;    } }If statement is used in above example. Type of user decides which message to return.Local state of component is useful in deciding the conditional rendering as state is flexible to change inside the component.Inline if with logical && operatorfunction MessageSizeChecker(props) {    const message = props.message;    return (       ... Read More