Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

Fixed an issue with nested contexts unwinding when server rendering. Issue #12984 #12985

Merged
merged 8 commits into from
Jun 11, 2018
Merged

Fixed an issue with nested contexts unwinding when server rendering. Issue #12984 #12985

Show file tree
Hide file tree
Changes from 2 commits
Commits
Show all changes
8 commits
Select commit Hold shift + click to select a range
8ff3f62
Fixed an issue with nested contexts unwinding when server rendering. …
ericsoderberghp Jun 5, 2018
27bb329
Fixed an issue with search direction and stricter false checking
ericsoderberghp Jun 5, 2018
8d38f45
Use decrement infix operator
ericsoderberghp Jun 5, 2018
037c4d5
Streamlined existence checks
ericsoderberghp Jun 5, 2018
e69904c
Streamlined assignment. Removed redundant comment. Use null for array…
ericsoderberghp Jun 6, 2018
731c686
Made prettier
ericsoderberghp Jun 6, 2018
6d31d3a
Relaxed type checking and improved comment
ericsoderberghp Jun 6, 2018
5114a3e
Improve test coverage
gaearon Jun 11, 2018
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
28 changes: 28 additions & 0 deletions packages/react-dom/src/__tests__/ReactDOMServerIntegrationNewContext-test.js
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -191,5 +191,33 @@ describe('ReactDOMServerIntegration', () => {
expect(e.querySelector('#theme').textContent).toBe('light');
expect(e.querySelector('#language').textContent).toBe('english');
});

itRenders(
'nested context unwinding',
async render => {
const Theme = React.createContext('dark');
const Language = React.createContext('french');

const App = () => (
<div>
<Theme.Provider value="light">
<Language.Provider>
<Theme.Provider value="dark">
<Theme.Consumer>
{theme => <div id="theme1">{theme}</div>}
</Theme.Consumer>
</Theme.Provider>
<Theme.Consumer>
{theme => <div id="theme2">{theme}</div>}
</Theme.Consumer>
</Language.Provider>
</Theme.Provider>
</div>
);
let e = await render(<App />);
expect(e.querySelector('#theme1').textContent).toBe('dark');
expect(e.querySelector('#theme2').textContent).toBe('light');
},
);
});
});
21 changes: 14 additions & 7 deletions packages/react-dom/src/server/ReactPartialRenderer.js
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -689,14 +689,21 @@ class ReactDOMServerRenderer {
this.providerStack[this.providerIndex] = null;
Copy link
Collaborator

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

What does .length assignment do in V8? I'd like to make sure it doesn't think the array length change is likely to "stay" because it changes all the time. I think just using null is more straightforward and less surprising to the engine (even though the typing isn't as nice for us).

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

OK. But, going back to using null seems to require testing for null when accessing array items by index, since Flow has been told that null and undefined are expected array item values. Or, is there an alternate Flow syntax that allows us to remove the explicit checks?

this.providerIndex -= 1;
const context: ReactContext<any> = provider.type._context;
if (this.providerIndex < 0) {
context._currentValue = context._defaultValue;
} else {
// We assume this type is correct because of the index check above.
const previousProvider: ReactProvider<any> = (this.providerStack[
this.providerIndex
]: any);
// find the correct previous provider based on type
Copy link
Collaborator

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

This comment is redundant, IMO the code speaks for itself

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

OK

let previousProvider;
if (this.providerIndex > -1) {
Copy link
Collaborator

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Seems like we can remove this condition? For loop already covers it.

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

OK.

for (let i = this.providerIndex; i >= 0; i -= 1) {
Copy link
Collaborator

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

If you don't mind, i-- would feel a bit more intuitive to me

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Done. I'm used to not allowing infix from our projects lint rules, old habits.

if (this.providerStack[i] !== null && this.providerStack[i] !== undefined &&
Copy link
Collaborator

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

So, do we actually need those checks? I wouldn't expect a provider "below" to ever be null. We only clear them out as we pop. As long as we check i doesn't get below zero we should be fine.

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Agreed. But, Flow doesn't seem to be aware of that. Perhaps we need some special Flow syntax I'm not aware of, which is highly likely?

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I addressed this by changing the array definition to be stricter and pop via setting the length. It didn't seem right to allow null as an array item but then not test for null when iterating over the array, even though the logic of how the array was being manipulated was OK.

(this.providerStack[i]: ReactProvider<any>).type === provider.type) {
Copy link
Collaborator

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

This comment was about why we felt comfortable using Flow any:

// We assume this type is correct because of the index check above.

Please keep it above the any case. Maybe change to "Flow type" to disambiguate.

// We assume this Flow type is correct because of the index check above.

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

OK.

previousProvider = this.providerStack[i];
break;
}
}
}
if (previousProvider) {
Copy link
Collaborator

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Let's initialize it to null and then compare to null instead of a truthy check.

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Good idea.

context._currentValue = previousProvider.props.value;
} else {
context._currentValue = context._defaultValue;
}
}

Expand Down