March 2017
Beginner to intermediate
500 pages
9h 41m
English
Content preview from React and React NativeBecome an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
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Cleaning up after components
In this final section of the chapter, we'll think about cleaning up after components. You don't have to explicitly unmount components from the DOM—React handles that for us. There are some things that React doesn't know about and therefore cannot clean up for us once the component is removed.
It's for these types of circumstance that the componentWillUnmount() lifecycle method exists. The main use case for cleaning up after React components is asynchronous code.
For example, imagine a component that issues an API call to fetch some data when the component is first mounted. Now, imagine that this component is removed from the DOM before the API response arrives.
Cleaning up asynchronous calls
If your asynchronous code tries ...
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.