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Outdated suggestions cannot be applied.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.
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.
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
[TS migration] Migrate 'FormElement.js' component to TypeScript #31012
[TS migration] Migrate 'FormElement.js' component to TypeScript #31012
Changes from 5 commits
78a09b7
af566d8
d340487
b52fbb3
b2dc291
7e7602f
1d8c3a3
5578518
f3133cb
30a3043
cadb376
627b85a
2571645
File filter
Filter by extension
Conversations
Jump to
There are no files selected for viewing
This file was deleted.
There was a problem hiding this comment.
Choose a reason for hiding this comment
The reason will be displayed to describe this comment to others. Learn more.
still don't get it why You need assertion here and why this assertion is different then defined ref in property. Could You explain?
There was a problem hiding this comment.
Choose a reason for hiding this comment
The reason will be displayed to describe this comment to others. Learn more.
Sure , here which is


SignInFormPage
for web platformwe are passing ref of type HTMLFormElement
but in
FormElement
we are usingView
whereView
expect ref to be a type ofView
Thats why we I need to assert it
There was a problem hiding this comment.
Choose a reason for hiding this comment
The reason will be displayed to describe this comment to others. Learn more.
The typing situation here is quite terrible. In React Native for Web,
View
component withrole={ComponentUtils.ACCESSIBILITY_ROLE_FORM}
will be backed by aHTMLFormElement
(which we can access through the ref), while neitherHTMLFormElement
is a subtype ofView
nor the other way around. In runtime, though, if I remember correctly, React Native for Web will patch the returned element, so in practice we could say that it does conform to theView
API.It doesn't help that in TypeScript
Object1
is assignable toObject2
in such scenario:...which is fundamentally unsound, as we can put a
123
insideprop1
ofObject1
through anObject2
reference without a single type assertion. I wasn't fully aware about this until today.This adds another layer of a mess to our situation, as you should't even be allowed to pass
MutableRefObject<HTMLFormElement>
toForwardRef<HTMLFormElement | View>
.I won't even start about how most refs don't even end-up being mutable, although they always should be, type-wise.
There was a problem hiding this comment.
Choose a reason for hiding this comment
The reason will be displayed to describe this comment to others. Learn more.
Having said all that, I think we add even more terrible typing to a pile of terrible typing.
I would just stick with
ForwardRef<View>
inFormElement
and cast once on the use-site (SignInPageForm
):And yes, the
as unknown
is necessary, because this is a terrible cast. We just were hiding it from the type system before. And yes, it's probably worth commenting.
There was a problem hiding this comment.
Choose a reason for hiding this comment
The reason will be displayed to describe this comment to others. Learn more.
Alternatively, we could remove the "force cast" (
as unknown as...
) by using a slightly bizarre cast......as
HTMLFormElement & View
is, actually, the most precise type for what this object should be in runtime on React Native for Web.There was a problem hiding this comment.
Choose a reason for hiding this comment
The reason will be displayed to describe this comment to others. Learn more.
is it a proper displayName? Doesn't follow file name
There was a problem hiding this comment.
Choose a reason for hiding this comment
The reason will be displayed to describe this comment to others. Learn more.
It was here before so I am not sure if this should be changed in TS migration
There was a problem hiding this comment.
Choose a reason for hiding this comment
The reason will be displayed to describe this comment to others. Learn more.
If you take a look at blame here they must've missed it.
Let's change it to 'FormElement' to follow the guidelines, other than that LGTM!