pure #13748
Merged
pure #13748
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
A higher-order component version of the `React.PureComponent` class. During an update, the previous props are compared to the new props. If they are the same, React will skip rendering the component and its children. Unlike userspace implementations, `pure` will not add an additional fiber to the tree. The first argument must be a functional component; it does not work with classes. `pure` uses shallow comparison by default, like `React.PureComponent`. A custom comparison can be passed as the second argument. Co-authored-by: Andrew Clark <[email protected]> Co-authored-by: Sophie Alpert <[email protected]>
|
React: size: 🔺+0.9%, gzip: 🔺+0.8% ReactDOM: size: 🔺+0.6%, gzip: 🔺+0.7% Details of bundled changes.Comparing: 4d17c3f...645a8ba react
react-dom
react-art
react-test-renderer
react-reconciler
react-native-renderer
scheduler
Generated by 🚫 dangerJS |
sophiebits
approved these changes
Sep 27, 2018
| workInProgress.childExpirationTime = current.childExpirationTime; | ||
| if (pendingProps !== current.pendingProps) { |
There was a problem hiding this comment.
What's the significance of this change?
There was a problem hiding this comment.
Previously the expirationTime field represented the pending priority of props, state, and context. In the begin phase, we check if this is lower priority than the render priority. If so, we can bail out.
After this change, it represents only the pending priority of state and context. The props check is moved to the begin phase. That way, in the begin phase, we can distinguish between an update caused by props versus an update caused by state or context. pure will never bail out if state or context has changed.
| @@ -124,7 +127,7 @@ export function reconcileChildren( | |||
| current: Fiber | null, | |||
| workInProgress: Fiber, | |||
| nextChildren: any, | |||
| renderExpirationTime: ExpirationTime, | |||
There was a problem hiding this comment.
Why is this here? Did prettier change?
| if (isLegacyContextProvider(Component)) { | ||
| pushLegacyContextProvider(workInProgress); | ||
|
|
||
| if (current !== null) { |
There was a problem hiding this comment.
I don't understand the significance of these changes either.
There was a problem hiding this comment.
Corresponds to the changes in https://github.com/facebook/react/pull/13748/files#r221093037
| } else { | ||
| const prototype = render.prototype; | ||
| if (!!(prototype && prototype.isReactComponent)) { | ||
| warningWithoutStack( |
There was a problem hiding this comment.
Unit tests for the warnings pls?
There was a problem hiding this comment.
sorry I could have also done this
sophiebits
reviewed
Sep 27, 2018
| ); | ||
| } | ||
| case PureComponentLazy: { |
There was a problem hiding this comment.
this duplication kills me a little bit :)
acdlite
force-pushed
the
pure
branch
2 times, most recently
from
5d22fe4
to
645a8ba
Compare
|
you missed a golden opportunity to call this |
|
It seems to be the first time React includes HOC in its public API. Do we need to expect some sort of new guides on when and how to use it? |
|
Agree with @alexbaumgertner , but IMO they will do that but just seems don't have much time currently, so before the release there will be blog post |
|
@acdlite Will DevTools need to be updated to recognize the new |
|
@alexeyraspopov We always include guides/docs/etc with releases. This is not a release yet. |
|
@acdlite Follow up facebook/react-devtools#1173 |
|
Maybe I'm misremembering, but wasn't one of the design goals of SFC to be pure by default? |
|
The goal was to make components easier to optimize. There are many ways to optimize, memoization based on shallow equality is just one possible optimization you can make. Functions already have less overhead since 16 (less property checks and memory usage), and they're also much more optimizable by compilers. Unfortunately our compilation experiments are still very early. |
|
Thanks for the explainer @gaearon 😄 |
acdlite
added a commit
to plievone/react
that referenced
this pull request
Oct 5, 2018
* pure A higher-order component version of the `React.PureComponent` class. During an update, the previous props are compared to the new props. If they are the same, React will skip rendering the component and its children. Unlike userspace implementations, `pure` will not add an additional fiber to the tree. The first argument must be a functional component; it does not work with classes. `pure` uses shallow comparison by default, like `React.PureComponent`. A custom comparison can be passed as the second argument. Co-authored-by: Andrew Clark <[email protected]> Co-authored-by: Sophie Alpert <[email protected]> * Warn if first argument is not a functional component
Merged
This was referenced Oct 24, 2018
This was referenced Nov 1, 2018
This was referenced Dec 1, 2018
jetoneza
pushed a commit
to jetoneza/react
that referenced
this pull request
Jan 23, 2019
* pure A higher-order component version of the `React.PureComponent` class. During an update, the previous props are compared to the new props. If they are the same, React will skip rendering the component and its children. Unlike userspace implementations, `pure` will not add an additional fiber to the tree. The first argument must be a functional component; it does not work with classes. `pure` uses shallow comparison by default, like `React.PureComponent`. A custom comparison can be passed as the second argument. Co-authored-by: Andrew Clark <[email protected]> Co-authored-by: Sophie Alpert <[email protected]> * Warn if first argument is not a functional component
NMinhNguyen
referenced
this pull request
in enzymejs/react-shallow-renderer
Jan 29, 2020
* pure A higher-order component version of the `React.PureComponent` class. During an update, the previous props are compared to the new props. If they are the same, React will skip rendering the component and its children. Unlike userspace implementations, `pure` will not add an additional fiber to the tree. The first argument must be a functional component; it does not work with classes. `pure` uses shallow comparison by default, like `React.PureComponent`. A custom comparison can be passed as the second argument. Co-authored-by: Andrew Clark <[email protected]> Co-authored-by: Sophie Alpert <[email protected]> * Warn if first argument is not a functional component
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Note: the discussion for this proposal is in reactjs/rfcs#63. It has since been renamed to
React.memo().A higher-order component version of the
React.PureComponentclass. During an update, the previous props are compared to the new props. If they are the same, React will skip rendering the component and its children.Unlike userspace implementations,
purewill not add an additional fiber to the tree.The first argument must be a functional component; it does not work with classes.
pureuses shallow comparison by default, likeReact.PureComponent. A custom comparison can be passed as the second argument.