![]() ![]() Only extend PureComponent when you expect to have simple props and state, or use forceUpdate() when you know deep data structures have changed. If these contain complex data structures, it may produce false-negatives for deeper differences. React.PureComponent’s shouldComponentUpdate() only shallowly compares the objects. If your React component’s render() function renders the same result given the same props and state, you can use React.PureComponent for a performance boost in some cases. The difference between them is that React.Component doesn’t implement shouldComponentUpdate(), but React.PureComponent implements it with a shallow prop and state comparison. React.PureComponent is similar to React.Component. Read the new React documentation for PureComponent. Hooks have a dedicated docs section and a separate API reference: They let you use state and other React features without writing a class. They allow you to mark updates as transitions, which tells React that they can be interrupted and avoid going back to Suspense fallbacks for already visible content. Transitions are a new concurrent feature introduced in React 18. In the future, it will support other use cases like data fetching. Today, Suspense only supports one use case: loading components dynamically with React.lazy. Suspense lets components “wait” for something before rendering. React also provides a component for rendering multiple elements without a wrapper. React provides several APIs for manipulating elements: See Using React without JSX for more information. You will not typically invoke the following methods directly if you are using JSX. Each JSX element is just syntactic sugar for calling React.createElement(). We recommend using JSX to describe what your UI should look like. React components can also be defined as functions which can be wrapped: See Using React without ES6 for more information. If you don’t use ES6 classes, you may use the create-react-class module instead. React components can be defined by subclassing React.Component or React.PureComponent. React components let you split the UI into independent, reusable pieces, and think about each piece in isolation. ![]() If you use ES5 with npm, you can write var React = require('react'). If you use ES6 with npm, you can write import React from 'react'. If you load React from a tag, these top-level APIs are available on the React global. React is the entry point to the React library. These new documentation pages teach modern React: You can read more about this in detail on React.Fragment vs. The only attribute you are likely to ever use with a Fragment is a key like we have talked about above, so as long as the key is not needed then it will be quicker and easier to make use of the shorthand. The shorthand version was introduced in React v16.2.0. ![]() The core difference between the longhand and shorthand React Fragment is that the shorthand does not support attributes whereas the longhand does. React fragment longhand vs React Fragment shorthand map ( ( ) Īs you can see in the above example we are using the “fruit” as the key because it is always unique within that array, and where we are creating a new component from for each “fruit” with multiple elements we need to wrap in in a fragment to have a single parent element.Īnd because we need to include a key we are therefore having to use the longhand version of a React Fragment. Here is an example of the longhand version of a React Fragment: However, we will go over this a little here later on in this post as well.įor now let’s take a look at how you can use both the longhand and shorthand versions of React Fragment. For more information on the differences between the two I highly recommend having a read through What are the differences between React.Fragment vs. We have the longhand version and the shorthand version. Thankfully using a React Fragment is nice and easy to do and we are provided with two different options from React. It probably won’t have a large effect if it is only done in one or two places but if used over a large application it can really save on the overall size of the DOM tree. This is why React Fragments are needed, but there is another use case where the HTML would be valid with or without an additional parent element and in these cases by using a React Fragment it helps to keep the overall size of the HTML DOM tree down which helps with performance. ![]()
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