8/3/2023 0 Comments React fragment map key![]() This only has a real benefit on very large and/or deep trees, but application performance often suffers from death by a thousand cuts. It’s a tiny bit faster and has less memory usage (no need to create an extra DOM node).Dan Abramov answered the question on StackOverflow. You may be looking for a good reason to use Fragments instead of the container div you have always been using. So instead of doing this: class Countries extends React.Component Question: Is a fragment better than a container div? The way out of that is to make use of a wrapper div or span element that acts as the enclosing tag. If you have ever tried to return more than one element, you know that you’ll will be greeted with this error: Syntax error: Adjacent JSX elements must be wrapped in an enclosing tag. It used to be that React components could only return a single element. These are new and really exciting concepts that came out of the React 16 release, so let’s look at them closer and get to know them. React 16 came with those goodies and much more, but In this post, we’ll be looking at the rendering power it also introduced - namely, the ability to render children using Fragments and Array Components. Originally published at on October 6, 2019.What comes to your mind when React 16 comes up? Context? Error Boundary? Those are on point. I also share exclusive tips and tricks for the newsletter subscribers! You can subscribe here. What do you think about React fragments and are you using them in your own projects? Please leave a comment below, I would love to hear from you!Īlso remember to subscribe to my newsletter, to stay tuned on the latest news and posts about modern web development. So the fact that fragments eliminate the wrapper div which can cause problems with invalid HTML and with styling of the components plus the fact that they are faster and the DOM is less cluttered, I’d say they are worth using. Some CSS mechanisms like Flexbox and CSS Grid have a special parent-child relationship, and adding divs in the middle makes it hard to keep the desired layout while extracting logical components.So are fragments worth using instead of say a wrapper div?ĭan Abramov answered this question on StackOverflow: It would probably look something like this.Įnter fullscreen mode Exit fullscreen mode This kind of behaviour results in useless markup and sometimes even invalid HTML to be rendered, which is bad.įor example we could have a component Table that renders an HTML table and inside that table the columns are rendered with another component called Columns. In most cases the wrapper div is “irrelevant” and is only added because React components require you to return only one element. Usually these elements are wrapped for example inside a div. So what are they and should you start using them? The answer to the latter is YES and the answer for the first question is what this blog post is going to tell you.Īre you new to React? Be sure to read my post 6 Things Every Beginner React Developer Should Know.Īs the React.js docs state, a common pattern in React is for components to return multiple elements. Even though they have been around for a while now, many React developers I have talked to haven’t started to use them yet and the number one reason for this usually is that they have heard of them but haven’t got around to learn about them. React Fragments were introduced in React 16.2.0.
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