React PureComponent可以比Component慢吗？ 怎么样？

Question

I'm referring to a post by Dan Abramov stating:

PSA: React.PureComponent can make your app slower if you use it everywhere.

(Dan's tweet on the topic)

Can someone elaborate on this? Thank you.

Answer 1

PureComponent implements a shouldComponentUpdate with shallow comparison of component state and props. It compares the currentProps against nextProps (similarly for state) and only if there is a change, the render method is invoked. The additional overhead of this comparison would definitely slow down the application especially if your component and state are heavy.