![]() Fragments let you group a list of children without adding extra nodes to the DOM. It doesn’t have to be separated out, you can inline it like you are doing at the minute, it just generally makes things a bit easier to grok and debug if you have it separated. A common pattern in React is for a component to return multiple elements. If children is a Fragment it will be treated as a single child and not traversed. If children is null or undefined, this method will return null or undefined rather than an array. but it leaves the door open to issues of scale or React changing how they deal with nested arrays/Fragments. So in React 16.2 version, Fragments were introduced, and we use them instead of the extraneous div tag. map () method and return a single element. If children is an array it will be traversed and the function will be called for each child in the array. The new React.Fragment feature lets us do this in an easy. Then in the parent component, have a key in state for the symbolArray, run the async fetch function in componentDidMount() and populate that piece of state with the result. To render multiple JSX elements in React, you can loop through an array with the. Normally the simplest way is to rely on the fact the React components rerender when props change. Note: Key is the only attributes that can be passed with the Fragments. React.Fragment was added in React version 16.2 because we always have to wrap multiple adjacent elements in some tag (like div) inside every JSX returned by a component. If you need to provide keys, you have to declare the fragments with the explicit React.Fragment> syntax. Because in React, every element in the array (when displayed using JSX) needs to have a unique key added to it. You need a key for mapping a collection to an array of fragments such as to create a description list. ![]() The thing you want doesn’t exist at the point in time you want to render it: getSymbolArray is async, so the return value is, practically, either going to be the array you want, or a promise saying you might get that array. The shorthand syntax does not accept key attributes. ![]() It’s because it’s trying to render an unresolved promise, which isn’t a thing you can render.
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