2/5/2024 0 Comments React fragment key attributesyntax supports a key attribute, while syntax - doesn't. What's the difference between those two syntaxes if the result is the same? There is a difference. Wait, do we have a typo there? No, we don't! The empty tags and is a short syntax for declaring Fragment in React 16. Now let's create our PublicListItems component: You can think of a Fragment type as an element that is invisible to the DOM. What will Fragment type render into the DOM? Nothing! And that's exactly what we want our PrivateListItems component to do: render only three li items, without rendering a parent element. It returns Fragment that wraps our three li items. Now let's take a look at our PrivateListItems component: ReactDOM.render(, document.getElementById("root")) Ĭhange userHasPermissions to userHasPermissions= and our App component will only render PublicListItems component. Now when we render our App component we can pass userHasPermissions prop to it only when the user is authenticated, for example: When the value is false our App component will not render component. When the value is true our App component will render component as a child. The userHasPermissions is a prop with a boolean value. Notice that use erHasPermissions prop and logical operator & to decide if we want to render component: For example, only authenticated users can see items that are private to them. Why do we want to separate those items into different React components? Imagine a scenario where all users can see public items, but only user with additional permissions can see private items. We have two separate React components responsible for rendering those items: Īs we've discussed earlier, our ul list is made of public and private li elements. The ul element has two child components: and. Bootstrap helps us create layout for our page. Our App component renders three div elements with class names that you might recognize if you're familiar with Bootstrap. Import PublicListItems from "./PublicListItems" Import PrivateListItems from "./PrivateListItems" Our application will be made of three React components:Īpp component is a container component - it encapsulates our entire React application, and renders PrivateListItems and PublicListItems as child components. Private items will be rendered by PrivateListItems component and public items will be rendered by PublicListItems component. This list will be made of private and public items. Our application is going to render a list of items. You can find the full source code in this GitHub repository. Let's demonstrate how to use fragments with the help of a simple React application: Figure 1. So the question is: how can React component render three li elements without rendering a parent element? We could wrap all three li elements in one parent element and return that element instead, but this will break our ul list. The rule is: a render() method in a React component must return only one element, not three li elements. Unfortunately, this is not possible in React 16. The problem is that both PrivateListItems and PublicListItems components need to return multiple elements, for example: Private items are rendered by PrivateListItems React component and public items by PublicListItems React component. They are grouped together and rendered by different React components. In this list you have two types of items: private and public. ![]() Because we provide a key, we have to type out "Fragment.Imagine your React app needs to render a list of items, for example: To avoid wrapping elements like a div, we use a fragment. You define a glossary component, rendering for each item, a pair of HTML elements - dt and td. In case you need a kit Fragment, we have to use Fragment directly. Same as our shell before, since it automatically desugars to React.Fragment. To make the offering experience as convenient as possible, the reacting addicts from tactical sugar for Fragment to JSX, since that of using React.Fragment, or importing it, we can simply use this syntax. ![]() If desired, we can also import Fragment from React and use it directly. By inspecting the DOM, we can see all of them are rendered inside the same unordered list element. One definite benefit here is that you can omit the keys. When using Fragment, no DOM element is rendered, and behaves as if your work return an array of elements. We can access it using React.Fragment, and use it to wrap a set of elements. In React 16.2, the Fragment component was added. We can extend this list using a fruits' component returning an array. Instructor: You can see an app rendering a list of fruits.
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